1000009800010@unknown@formal@none@1@S@⌊δWordPerfectδ⌋@@@@1@1@@oe@26-8-2013 1000009800020@unknown@formal@none@1@S@⌊∗WordPerfect∗⌋ is a ⌊>proprietary>⌋ ⌊>word processing>⌋ application.@@@@1@7@@oe@26-8-2013 1000009800030@unknown@formal@none@1@S@At the height of its popularity in the late 1980s and early 1990s, it was the ⌊/⌊>de facto>⌋/⌋ standard word processor, but has since been eclipsed in sales by ⌊>Microsoft Word>⌋.@@@@1@31@@oe@26-8-2013 1000009800040@unknown@formal@none@1@S@Although the ⌊>MS-DOS>⌋ and ⌊>Microsoft Windows>⌋ versions are best known, its popularity was based on the fact that it had been available for a wide variety of computers and operating systems, including ⌊>Mac OS>⌋, ⌊>Linux>⌋, the ⌊>Apple IIe>⌋, a separate version for the ⌊>Apple IIgs>⌋, most popular versions of ⌊>Unix>⌋, ⌊>VMS>⌋, ⌊>Data General>⌋, ⌊>System/370>⌋, ⌊>AmigaOS>⌋, ⌊>Atari ST>⌋, ⌊>OS/2>⌋, and ⌊>NeXTSTEP>⌋.@@@@1@60@@oe@26-8-2013 1000009800050@unknown@formal@none@1@S@⌊=WordPerfect for DOS¦2=⌋@@@@1@3@@oe@26-8-2013 1000009800060@unknown@formal@none@1@S@WordPerfect was originally produced by ⌊>Bruce Bastian>⌋ and Dr. ⌊>Alan Ashton>⌋ who founded Satellite Software International, Inc. of ⌊>Orem>⌋, ⌊>Utah>⌋, which later renamed itself WordPerfect Corporation.@@@@1@26@@oe@26-8-2013 1000009800070@unknown@formal@none@1@S@Originally written for ⌊>Data General>⌋ minicomputers, in 1982 the developers ported the program to the IBM PC as WordPerfect 2.20, continuing the version numbering of the Data General series.@@@@1@29@@oe@26-8-2013 1000009800080@unknown@formal@none@1@S@The program's popularity took off with the introduction of WordPerfect 4.2 in 1986, with automatic paragraph numbering (important to the law office market), and the splitting of a lengthy footnote and its partial overflow to the bottom of the next page, as if it had been professionally typeset (valuable to both the law office and academic markets).@@@@1@57@@oe@26-8-2013 1000009800090@unknown@formal@none@1@S@WordPerfect 4.2 became the first program to overtake the original microcomputer word processor market leader, ⌊>WordStar>⌋, in a major application category on the ⌊>DOS>⌋ platform.@@@@1@25@@oe@26-8-2013 1000009800100@unknown@formal@none@1@S@In 1989, WordPerfect Corporation released the program's most successful version ever, WordPerfect 5.1 for DOS, which was the first version to include ⌊>Macintosh>⌋ style pull-down menus to supplement the traditional F-key combinations, as well as support for tables, a spreadsheet-like feature.@@@@1@41@@oe@26-8-2013 1000009800110@unknown@formal@none@1@S@The data format used by WordPerfect 5.1 was, for years, the most portable format in the world.@@@@1@17@@oe@26-8-2013 1000009800120@unknown@formal@none@1@S@All word processors could read (and convert) that format.@@@@1@9@@oe@26-8-2013 1000009800130@unknown@formal@none@1@S@Many conferences and magazines insisted that you shipped your documents in 5.1 format.@@@@1@13@@oe@26-8-2013 1000009800140@unknown@formal@none@1@S@Unlike previous DOS versions, WordPerfect 6.0 for DOS could switch between its traditional text-based editing mode and a graphical editing mode that ⌊>showed the document as it would print out>⌋, including fonts and text effects like bold, underline, and italics.@@@@1@40@@oe@26-8-2013 1000009800150@unknown@formal@none@1@S@The previous text-based versions used different colors or text color inversions to indicate various markups, and (starting with version 5.0) used a graphic mode only for an uneditable print preview that used generic fonts rather than the actual fonts that appeared on the printed page.@@@@1@45@@oe@26-8-2013 1000009800160@unknown@formal@none@1@S@⌊=Key characteristics¦3=⌋@@@@1@2@@oe@26-8-2013 1000009800170@unknown@formal@none@1@S@To this day, WordPerfect's three major characteristics that have differentiated from other market-leading word processors are its streaming code architecture, its Reveal Codes feature, and its unusually user-friendly macro/scripting language, PerfectScript.@@@@1@31@@oe@26-8-2013 1000009800180@unknown@formal@none@1@S@⌊=Streaming code architecture¦4=⌋@@@@1@3@@oe@26-8-2013 1000009800190@unknown@formal@none@1@S@A key to WordPerfect's design is its streaming code architecture that parallels the formatting features of ⌊>HTML>⌋ and ⌊>Cascading Style Sheets>⌋.@@@@1@21@@oe@26-8-2013 1000009800200@unknown@formal@none@1@S@Documents are created much the same way that raw HTML pages are written, with text interspersed by tags that trigger treatment of data until a corresponding closing tag is encountered, at which point the settings active to the point of the opening tag resume control.@@@@1@45@@oe@26-8-2013 1000009800210@unknown@formal@none@1@S@As with HTML, tags can be nested.@@@@1@7@@oe@26-8-2013 1000009800220@unknown@formal@none@1@S@Some data structures are treated as objects within the stream as with HTML's treatment of graphic images, e.g., footnotes and styles, but the bulk of a WordPerfect document's data and formatting codes appear as a single continuous stream.@@@@1@38@@oe@26-8-2013 1000009800230@unknown@formal@none@1@S@⌊=Styles and style libraries¦4=⌋@@@@1@4@@oe@26-8-2013 1000009800240@unknown@formal@none@1@S@The addition of styles and style libraries in WP 5.0 provided greatly increased power and flexibility in formatting documents, while maintaining the streaming-code architecture of earlier versions.@@@@1@27@@oe@26-8-2013 1000009800250@unknown@formal@none@1@S@Prior to that, WordPerfect's only use of styles (a particular type of programming object) is the Opening Style, which contains the default settings for a document.@@@@1@26@@oe@26-8-2013 1000009800260@unknown@formal@none@1@S@⌊=Reveal codes¦4=⌋@@@@1@2@@oe@26-8-2013 1000009800270@unknown@formal@none@1@S@The Reveal Codes feature is a second editing screen that can be toggled open and closed at the bottom of the main editing screen.@@@@1@24@@oe@26-8-2013 1000009800280@unknown@formal@none@1@S@Text is displayed in Reveal Codes interspersed with tags and the occasional objects, with the tags and objects represented by named tokens.@@@@1@22@@oe@26-8-2013 1000009800290@unknown@formal@none@1@S@The scheme makes it far easier to untangle coding messes than with styles-based word processors, and object tokens can be clicked with a pointing device to directly open the configuration editor for the particular object type, e.g. clicking on a style token brings up the style editor with the particular style type displayed.@@@@1@53@@oe@26-8-2013 1000009800300@unknown@formal@none@1@S@WordPerfect users forced to change word processors by employers frequently complain on WordPerfect online forums that they are lost without Reveal Codes.@@@@1@22@@oe@26-8-2013 1000009800310@unknown@formal@none@1@S@Because of their style dependencies, efforts to create the equivalent of Reveal Codes in other word processors have produced disappointing results.@@@@1@21@@oe@26-8-2013 1000009800320@unknown@formal@none@1@S@Note that WordPerfect had this feature already in its DOS incarnations: it could be brought forward by pressing the keys 'Alt' and 'F3' together.@@@@1@24@@oe@26-8-2013 1000009800330@unknown@formal@none@1@S@⌊=Macro languages¦4=⌋@@@@1@2@@oe@26-8-2013 1000009800340@unknown@formal@none@1@S@WordPerfect for DOS was notable for its Alt-keystroke macro facility, which was expanded with the addition of macro libraries in WP 5.0 that also allowed for Ctrl-keystroke macros, and remapping of any key as a macro.@@@@1@36@@oe@26-8-2013 1000009800350@unknown@formal@none@1@S@This enabled any sequence of keystrokes to be recorded, saved, edited, and recalled.@@@@1@13@@oe@26-8-2013 1000009800360@unknown@formal@none@1@S@Macros could examine system data, make decisions, be chained together, and operate recursively until a defined 'stop' condition was met.@@@@1@20@@oe@26-8-2013 1000009800370@unknown@formal@none@1@S@This capability provided an amazingly powerful way to rearrange data and formatting codes within a document, where the same sequence of actions needed to be performed repetitively e.g. for tabular data.@@@@1@31@@oe@26-8-2013 1000009800380@unknown@formal@none@1@S@Macros can also be edited using WordPerfect Program Editor.@@@@1@9@@oe@26-8-2013 1000009800390@unknown@formal@none@1@S@Unfortunately, this facility could not easily be ported to the subsequent Windows versions.@@@@1@13@@oe@26-8-2013 1000009800400@unknown@formal@none@1@S@A new and even more powerful interpreted token-based macro recording and scripting language was introduced for both DOS and Windows 6.0 versions, and that became the basis of the language named PerfectScript in later versions.@@@@1@35@@oe@26-8-2013 1000009800410@unknown@formal@none@1@S@PerfectScript has remained the mainstay scripting language for WordPerfect users ever since.@@@@1@12@@oe@26-8-2013 1000009800420@unknown@formal@none@1@S@PerfectScript was specifically designed to be user-friendly, thus avoiding far less user-friendly methods of scripting languages implemented on other word processing programs that require education in advanced programming concepts such as Object Oriented Programming in order to produce useful yet sophisticated and powerful macros.@@@@1@44@@oe@26-8-2013 1000009800430@unknown@formal@none@1@S@⌊=Function keys¦3=⌋@@@@1@2@@oe@26-8-2013 1000009800440@unknown@formal@none@1@S@Like its mid-1980s competitor, ⌊>MultiMate>⌋, WordPerfect used almost every possible combination of ⌊>function key>⌋s with Ctrl, Alt, and Shift modifiers.@@@@1@20@@oe@26-8-2013 1000009800450@unknown@formal@none@1@S@(⌊>See example help screen on this page>⌋.)@@@@1@7@@oe@26-8-2013 1000009800460@unknown@formal@none@1@S@This was in contrast to ⌊>WordStar>⌋, which used only Ctrl, in conjunction with traditional typing keys.@@@@1@16@@oe@26-8-2013 1000009800470@unknown@formal@none@1@S@Many people still know and use the ⌊>function key>⌋ combinations from the DOS version, which were originally designed for Data General Dasher VDUs that supported 2 groups of 5 plain, shift, control, and control shift function keys.@@@@1@37@@oe@26-8-2013 1000009800480@unknown@formal@none@1@S@This was translated to the layout of the 1981 ⌊>IBM PC keyboard>⌋, with two columns of function keys at the left end of the keyboard, but worked even better with the 1984 PC AT keyboard with 3 groups of 4 function keys across the top of the keyboard.@@@@1@48@@oe@26-8-2013 1000009800490@unknown@formal@none@1@S@With the 1981 PC keyboard, the Tab key and the related F4 (⌊/Indent/⌋) functions were adjacent.@@@@1@16@@oe@26-8-2013 1000009800500@unknown@formal@none@1@S@This plethora of keystroke possibilities, combined with the developers' wish to keep the user interface free of "clutter" such as on-screen menus, made it necessary for most users to use a keyboard template showing each function.@@@@1@36@@oe@26-8-2013 1000009800510@unknown@formal@none@1@S@Infamously, WordPerfect used F3 instead of F1 for ⌊/Help/⌋, F1 instead of Esc for ⌊/Cancel/⌋, and Esc for ⌊/Repeat/⌋ (though a configuration option in later versions allowed these functions to be rotated to locations that later became more standard).@@@@1@39@@oe@26-8-2013 1000009800520@unknown@formal@none@1@S@⌊=Printer drivers¦3=⌋@@@@1@2@@oe@26-8-2013 1000009800530@unknown@formal@none@1@S@WordPerfect for DOS shipped with an impressive array of printer drivers - a feature that played an important role in its adoption - and also shipped with a ⌊>printer driver>⌋ editor called PTR, which features a flexible ⌊>macro language>⌋ and allows technically-inclined users to customize and create printer drivers.@@@@1@49@@oe@26-8-2013 1000009800540@unknown@formal@none@1@S@Internally, WordPerfect used an extensive WordPerfect ⌊>character set>⌋ as its ⌊>internal code>⌋.@@@@1@12@@oe@26-8-2013 1000009800550@unknown@formal@none@1@S@The precise meaning of the characters, although clearly defined and documented, can be overridden in its customizable printer drivers with PTR.@@@@1@21@@oe@26-8-2013 1000009800560@unknown@formal@none@1@S@The relationship between different type faces and styles, and between them and the various sections in the WordPerfect character set, were also described in the printer drivers and can be customized through PTR.@@@@1@33@@oe@26-8-2013 1000009800570@unknown@formal@none@1@S@⌊=WordPerfect Library/Office¦3=⌋@@@@1@2@@oe@26-8-2013 1000009800580@unknown@formal@none@1@S@WordPerfect Corporation produced a variety of ancillary and spin-off products.@@@@1@10@@oe@26-8-2013 1000009800590@unknown@formal@none@1@S@WordPerfect Library (introduced in 1986 and later renamed WordPerfect Office) was a package of network and stand-alone utilities for use with WordPerfect, primarily developed for offices running ⌊>Novell NetWare>⌋.@@@@1@29@@oe@26-8-2013 1000009800600@unknown@formal@none@1@S@WordPerfect Library/Office included the DOS antecedents of what is now known as ⌊>Novell GroupWise>⌋, a shareable package of contact management, calendaring, and related word processing utilities.@@@@1@26@@oe@26-8-2013 1000009800610@unknown@formal@none@1@S@WordPerfect Library/Office a brand name later revived by Corel after it acquired ownership of WordPerfect and other programs still bundled under that product name as of this writing – included amongst other utilities a local area network (LAN) email facility and was the most popular such package in its day.@@@@1@50@@oe@26-8-2013 1000009800620@unknown@formal@none@1@S@⌊=WordPerfect Shell¦4=⌋@@@@1@2@@oe@26-8-2013 1000009800630@unknown@formal@none@1@S@The Library/Office bundle also included a noteworthy task-switching program that ran as a shell atop DOS, branded as WordPerfect Shell.@@@@1@20@@oe@26-8-2013 1000009800640@unknown@formal@none@1@S@Task-switchers were a popular application type for the DOS operating system because of its lack of multi-tasking, making it impractical to have many applications running at once.@@@@1@27@@oe@26-8-2013 1000009800650@unknown@formal@none@1@S@Task-switchers were programs that allocated available memory between open applications, allowing fast switching between open applications whose actions were suspended when the user switched to a different program.@@@@1@28@@oe@26-8-2013 1000009800660@unknown@formal@none@1@S@WordPerfect Shell 4.0, which was also bundled with the WordPerfect 6.x versions, had most functionality of the Windows 3.x shell but was far more versatile.@@@@1@25@@oe@26-8-2013 1000009800670@unknown@formal@none@1@S@Its automated memory management was superior to that of the Microsoft Windows shell, and Microsoft's product generally performed with far less frequent memory glitches when Windows was run as a program under Shell 4.0.@@@@1@34@@oe@26-8-2013 1000009800680@unknown@formal@none@1@S@The user interface for Shell is based on a hierarchical menu metaphor rather than the windows/folders/icons metaphor used by Microsoft.@@@@1@20@@oe@26-8-2013 1000009800690@unknown@formal@none@1@S@Shell 4.0's menu structures could be individually hot-keyed as pop-ups and its powerful menu editor allowed fast creation and editing of menu structures and menu items, with each menu item quickly configurable for entry of command lines and menu names.@@@@1@40@@oe@26-8-2013 1000009800700@unknown@formal@none@1@S@Shell 4.0 included 80 programmable clipboards, and the menu structures and menu items were also programmable using a scripting language whose scripts could themselves be chained to and from WordPerfect macros.@@@@1@31@@oe@26-8-2013 1000009800710@unknown@formal@none@1@S@The scripting language also included a keyboard buffer stuffing tool for control and operation of non-WordPerfect applications.@@@@1@17@@oe@26-8-2013 1000009800720@unknown@formal@none@1@S@Microsoft Windows had no answer to such powerful features other than a glitz of windows, icons, pointing devices, and an overwhelming marketing strategy.@@@@1@23@@oe@26-8-2013 1000009800730@unknown@formal@none@1@S@WordPerfect Shell was laid to rest along with many other popular DOS character-based tools inundated by Microsoft's marketing of Windows 95.@@@@1@21@@oe@26-8-2013 1000009800740@unknown@formal@none@1@S@Novell later licensed Shell 3.0 and 4.0 for free distribution.@@@@1@10@@oe@26-8-2013 1000009800750@unknown@formal@none@1@S@As of this writing it is still downloadable from the DataPerfect Users Group.@@@@1@13@@oe@26-8-2013 1000009800760@unknown@formal@none@1@S@WordPerfect Library/Office also included a Calculator, a flat-file database called Notebook that could be used by itself or in WordPerfect document merges, an exceptionally powerful relational database - ⌊>DataPerfect>⌋ - that retains a small but dedicated following despite having been dropped by WordPerfect Corporation in favour of Borland's Paradox as a companion of WP for Windows.@@@@1@56@@oe@26-8-2013 1000009800770@unknown@formal@none@1@S@Additional features continue to be added from time to time by DataPerfect's author, Lew Bastian - Bruce Bastian's older brother - a brilliant programmer who had written some of IBM's earliest disk-caching patents, and DataPerfect can now run as web server.@@@@1@41@@oe@26-8-2013 1000009800780@unknown@formal@none@1@S@LetterPerfect was a scaled down version of WordPerfect with the more advanced features removed but with file and (for the most part) keystroke compatibility.@@@@1@24@@oe@26-8-2013 1000009800790@unknown@formal@none@1@S@An implementation of Microsoft Visual Basic for Applications (VBA), introduced with WordPerfect for Windows 9.0, provides a full-featured development environment for building advanced custom WordPerfect solutions.@@@@1@26@@oe@26-8-2013 1000009800800@unknown@formal@none@1@S@These solutions are often created by corporate developers or programmers and may not be easily accessible to the typical WordPerfect user.@@@@1@21@@oe@26-8-2013 1000009800810@unknown@formal@none@1@S@For these users, PerfectScript is the better option.@@@@1@8@@oe@26-8-2013 1000009800820@unknown@formal@none@1@S@People who code scripts for WordPerfect use the Macros & Merges forum at WordPerfect Universe as their primary meeting ground.@@@@1@20@@oe@26-8-2013 1000009800830@unknown@formal@none@1@S@That site is a collaboration among other WordPerfect-related web site operators and others and functions as a portal to WordPerfect resources on the web.@@@@1@24@@oe@26-8-2013 1000009800840@unknown@formal@none@1@S@The site also maintains an extensive clip library for use in PerfectScript programming, has the Web's largest metalink library for locating online WordPerfect resources, and has the only peer-to-peer forum on the Web for DOS WordPerfect.@@@@1@36@@oe@26-8-2013 1000009800850@unknown@formal@none@1@S@The WordPerfect template and document file formats have remained remarkably stable since the WordPerfect 6.x DOS and Windows versions.@@@@1@19@@oe@26-8-2013 1000009800860@unknown@formal@none@1@S@Complete backward compatibility has been maintained and all WordPerfect versions since 6.0 have included a feature that stores any unrecognized codes in stream location represented in Reveal Codes by an "Unknown" token.@@@@1@32@@oe@26-8-2013 1000009800870@unknown@formal@none@1@S@Documents generated on newer versions can thus be edited in older versions with the codes retained.@@@@1@16@@oe@26-8-2013 1000009800880@unknown@formal@none@1@S@Then, upon being reopened in a newer version of WordPerfect, the "unknown" tokens regain their functionality.@@@@1@16@@oe@26-8-2013 1000009800890@unknown@formal@none@1@S@None of the newer WordPerfect features reflected in the file formats cause data loss when opened in older versions.@@@@1@19@@oe@26-8-2013 1000009800900@unknown@formal@none@1@S@⌊=WordPerfect for Windows¦2=⌋@@@@1@3@@oe@26-8-2013 1000009800910@unknown@formal@none@1@S@⌊=History¦3=⌋@@@@1@1@@oe@26-8-2013 1000009800920@unknown@formal@none@1@S@WordPerfect was late in coming to market with a Windows version.@@@@1@11@@oe@26-8-2013 1000009800930@unknown@formal@none@1@S@The first mature version, WordPerfect 5.2 for Windows, was released in November ⌊>1992>⌋.@@@@1@13@@oe@26-8-2013 1000009800940@unknown@formal@none@1@S@Prior to that, there was a WordPerfect 5.1 for Windows, introduced a year earlier.@@@@1@14@@oe@26-8-2013 1000009800950@unknown@formal@none@1@S@That version had to be installed from DOS and was largely unpopular due to serious stability issues.@@@@1@17@@oe@26-8-2013 1000009800960@unknown@formal@none@1@S@By the time WordPerfect 5.2 for Windows was introduced, ⌊>Microsoft Word for Windows>⌋ version 2 had been on the market for over a year and had received its third interim release, v2.0c. WordPerfect's function-key-centered user interface did not adapt well to the new paradigm of mouse and pull-down menus, especially with many of WordPerfect's standard key combinations pre-empted by incompatible keyboard shortcuts that Windows itself used (e.g. Alt-F4 became ⌊/Exit Program/⌋ as opposed to WordPerfect's ⌊/Block Text/⌋).@@@@1@77@@oe@26-8-2013 1000009800970@unknown@formal@none@1@S@The DOS version's impressive arsenal of finely tuned printer drivers was also rendered obsolete by Windows' use of its own printer device drivers.@@@@1@23@@oe@26-8-2013 1000009800980@unknown@formal@none@1@S@Internally, WordPerfect for Windows still used the WordPerfect character set as its internal code.@@@@1@14@@oe@26-8-2013 1000009800990@unknown@formal@none@1@S@This caused WordPerfect for Windows to be unable to support some languages — for example ⌊>Chinese>⌋ — that were natively supported by Windows.@@@@1@23@@oe@26-8-2013 1000009801000@unknown@formal@none@1@S@WordPerfect became part of an ⌊>office suite>⌋ when the company entered into a co-licensing agreement with ⌊>Borland Software Corporation>⌋ in 1993.@@@@1@21@@oe@26-8-2013 1000009801010@unknown@formal@none@1@S@The offerings were marketed as Borland Office, containing Windows versions of WordPerfect, ⌊>Quattro Pro>⌋, ⌊>Borland Paradox>⌋, and a LAN-based groupware package called WordPerfect Office (not to be confused with the complete applications suite of the same name later marketed by Corel) based on the WordPerfect Library for DOS.@@@@1@48@@oe@26-8-2013 1000009801020@unknown@formal@none@1@S@The WordPerfect product line was sold twice, first to ⌊>Novell>⌋ in June ⌊>1994>⌋, who then sold it to ⌊>Corel>⌋ in January ⌊>1996>⌋.@@@@1@22@@oe@26-8-2013 1000009801030@unknown@formal@none@1@S@However, Novell kept the WordPerfect Office technology, incorporating it into its ⌊>GroupWise>⌋ messaging and collaboration product.@@@@1@16@@oe@26-8-2013 1000009801040@unknown@formal@none@1@S@Compounding WordPerfect's troubles were issues associated with the release of the first ⌊>32-bit>⌋ version, WordPerfect 7, intended for use on ⌊>Windows 95>⌋.@@@@1@22@@oe@26-8-2013 1000009801050@unknown@formal@none@1@S@While it contained notable improvements over the ⌊>16-bit>⌋ WordPerfect for Windows 6.1, it was released in May ⌊>1996>⌋, nine months after the introduction of Windows 95 and Microsoft Office 95 (including ⌊>Word 95>⌋).@@@@1@33@@oe@26-8-2013 1000009801060@unknown@formal@none@1@S@The initial release suffered from notable stability problems.@@@@1@8@@oe@26-8-2013 1000009801070@unknown@formal@none@1@S@WordPerfect 7 also didn't have a Microsoft "Designed for Windows 95" logo.@@@@1@12@@oe@26-8-2013 1000009801080@unknown@formal@none@1@S@This was important to Windows 95 software purchasers as Microsoft set standards for application design, behavior, and interaction with the operating system.@@@@1@22@@oe@26-8-2013 1000009801090@unknown@formal@none@1@S@To make matters worse, the original release of WordPerfect 7 was incompatible with ⌊>Windows NT>⌋, hindering its adoption in academia.@@@@1@20@@oe@26-8-2013 1000009801100@unknown@formal@none@1@S@The "NT Enabled" version of WordPerfect 7, which Corel considered to be Service Pack 2, wasn't available until Q1-⌊>1997>⌋, over 6 months after the introduction of ⌊>Windows NT 4.0>⌋, a year and a half after the introduction of Office 95 (which supported Windows NT out of the box), and shortly after the introduction of Office 97.@@@@1@56@@oe@26-8-2013 1000009801110@unknown@formal@none@1@S@Corel charged its customers to receive, what amounted to, a bug fix.@@@@1@12@@oe@26-8-2013 1000009801120@unknown@formal@none@1@S@While WordPerfect retained a majority of the retail shelf sales of word processors, Microsoft gained marketshare by including ⌊>Word for Windows>⌋ in its Windows product on new PCs.@@@@1@28@@oe@26-8-2013 1000009801130@unknown@formal@none@1@S@Microsoft gave discounts for Windows to OEMs who included Word on their PCs.@@@@1@13@@oe@26-8-2013 1000009801140@unknown@formal@none@1@S@When new PC buyers found Word installed on their new PC, Word began to dominate marketshare of desktop word processing.@@@@1@20@@oe@26-8-2013 1000009801150@unknown@formal@none@1@S@Amongst the remaining avid users of WordPerfect are many law firms and academics who favor the WordPerfect features such as macros and reveal codes.@@@@1@24@@oe@26-8-2013 1000009801160@unknown@formal@none@1@S@Corel now caters to these markets, with, for example, a major sale to the ⌊>United States Department of Justice>⌋ in 2005 .@@@@1@22@@oe@26-8-2013 1000009801170@unknown@formal@none@1@S@In November 2004, Novell filed an antitrust lawsuit against Microsoft for alleged anticompetitive behavior (viz, tying Word to sales of Windows) that Novell claims led to loss of WordPerfect market share .@@@@1@32@@oe@26-8-2013 1000009801180@unknown@formal@none@1@S@⌊=Corel WordPerfect¦3=⌋@@@@1@2@@oe@26-8-2013 1000009801190@unknown@formal@none@1@S@Since its acquisition by ⌊>Corel>⌋, WordPerfect for Windows has officially been known as ⌊∗Corel WordPerfect∗⌋.@@@@1@15@@oe@26-8-2013 1000009801200@unknown@formal@none@1@S@⌊=Unicode and Asian language editing¦2=⌋@@@@1@5@@oe@26-8-2013 1000009801210@unknown@formal@none@1@S@WordPerfect also lacks support for ⌊>Unicode>⌋.@@@@1@6@@oe@26-8-2013 1000009801220@unknown@formal@none@1@S@The absence of support for ⌊>Unicode>⌋ limits its usefulness in many markets outside North America and Western Europe.@@@@1@18@@oe@26-8-2013 1000009801230@unknown@formal@none@1@S@Despite pleas from longtime users, this feature has not been implemented as of yet.@@@@1@14@@oe@26-8-2013 1000009801240@unknown@formal@none@1@S@For users in WordPerfect's traditional markets, the inability to deal with complex character sets, such as Asian language scripts, can cause difficulty when working on documents containing those characters.@@@@1@29@@oe@26-8-2013 1000009801250@unknown@formal@none@1@S@However, later versions have provided better compliance with interface conventions, file compatibility, and even Word interface emulation.@@@@1@17@@oe@26-8-2013 1000009801260@unknown@formal@none@1@S@⌊=WordPerfect for Macintosh¦2=⌋@@@@1@3@@oe@26-8-2013 1000009801270@unknown@formal@none@1@S@Development of WordPerfect for Macintosh did not run parallel to versions for other operating systems, and used version numbers unconnected to contemporary releases for DOS, Windows, etc.@@@@1@27@@oe@26-8-2013 1000009801280@unknown@formal@none@1@S@The first release reminded users and reviewers of the DOS version, and was not especially successful in the marketplace.@@@@1@19@@oe@26-8-2013 1000009801290@unknown@formal@none@1@S@Version 2 was a total re-write, adhering more closely to Apple's UI guidelines.@@@@1@13@@oe@26-8-2013 1000009801300@unknown@formal@none@1@S@Version 3 took this further, making extensive use of the technologies Apple introduced in Systems 7.0–7.5, while remaining fast and capable of running well on older machines.@@@@1@27@@oe@26-8-2013 1000009801310@unknown@formal@none@1@S@Corel released version 3.5 in 1996, followed by the improved version 3.5e.@@@@1@12@@oe@26-8-2013 1000009801320@unknown@formal@none@1@S@It was never updated beyond that, and the product was eventually discontinued.@@@@1@12@@oe@26-8-2013 1000009801330@unknown@formal@none@1@S@⌊>As of 2004>⌋, Corel has reiterated that the company has no plans to further develop WordPerfect for Macintosh (such as creating a native Mac OS X version).@@@@1@27@@oe@26-8-2013 1000009801340@unknown@formal@none@1@S@For several years, Corel allowed Mac users to download version 3.5e from their website free of charge, and some Mac users still use this version.@@@@1@25@@oe@26-8-2013 1000009801350@unknown@formal@none@1@S@The download is still available, along with the necessary OS 8/9/Classic Updater that slows scroll speed and restores functionality to the Style and Window menus.@@@@1@25@@oe@26-8-2013 1000009801360@unknown@formal@none@1@S@Like other Mac OS applications of its age, it requires the Classic environment on ⌊>PowerPC>⌋ Macs.@@@@1@16@@oe@26-8-2013 1000009801370@unknown@formal@none@1@S@While Intel Macs do not support Classic, emulators such as ⌊>SheepShaver>⌋, and ⌊>vMac>⌋ allow users to run WordPerfect and other Mac OS applications.@@@@1@23@@oe@26-8-2013 1000009801380@unknown@formal@none@1@S@Users wishing to use an up to date version of WordPerfect can run the Windows version through ⌊>Boot Camp>⌋ or a Windows emulator, and through ⌊>Darwine>⌋ or ⌊>CrossOver Mac>⌋ with mixed results.@@@@1@32@@oe@26-8-2013 1000009801390@unknown@formal@none@1@S@⌊=WordPerfect for Linux¦2=⌋@@@@1@3@@oe@26-8-2013 1000009801400@unknown@formal@none@1@S@In 1995, WordPerfect 6.0 was made available for ⌊>Linux>⌋ as part of ⌊>Caldera>⌋'s internet office package.@@@@1@16@@oe@26-8-2013 1000009801410@unknown@formal@none@1@S@In late 1997, a newer version was made available for download, but had to be purchased to be activated.@@@@1@19@@oe@26-8-2013 1000009801420@unknown@formal@none@1@S@Hoping to establish themselves in the nascent commercial Linux market, Corel also developed their ⌊>own distribution>⌋ of Linux.@@@@1@18@@oe@26-8-2013 1000009801430@unknown@formal@none@1@S@Although the Linux distribution was fairly well-received, the response to WordPerfect for Linux was varied.@@@@1@15@@oe@26-8-2013 1000009801440@unknown@formal@none@1@S@Some Linux promoters appreciated the availability of a well-known, mainstream application for the OS. Developers of other Linux-compatible word processors questioned the need for another application in the category.@@@@1@29@@oe@26-8-2013 1000009801450@unknown@formal@none@1@S@Advocates of ⌊>open-source software>⌋ scoffed at its proprietary, closed-source nature, and questioned the viability of a commercial application in a market dominated by free software, such as ⌊>OpenOffice.org>⌋ and numerous others.@@@@1@31@@oe@26-8-2013 1000009801460@unknown@formal@none@1@S@The performance and stability of WordPerfect 9.0 (not a native Linux application like WP 6-8, but derived from the Windows version using the ⌊>Wine>⌋ compatibility library) was highly criticized.@@@@1@29@@oe@26-8-2013 1000009801470@unknown@formal@none@1@S@WordPerfect failed to gain a large user base, and as part of Corel's change of strategic direction following a (non-voting) investment by Microsoft, WordPerfect for Linux was discontinued and their Linux distribution was sold to ⌊>Xandros>⌋.@@@@1@36@@oe@26-8-2013 1000009801480@unknown@formal@none@1@S@In April 2004, Corel re-released WordPerfect 8.1 (the last Linux-native version) with some updates, as a "proof of concept" and to test the Linux market.@@@@1@25@@oe@26-8-2013 1000009801490@unknown@formal@none@1@S@⌊>As of 2005>⌋, WordPerfect for Linux is not available for purchase.@@@@1@11@@oe@26-8-2013 1000009801500@unknown@formal@none@1@S@⌊=Versions¦2=⌋@@@@1@1@@oe@26-8-2013 1000009801510@unknown@formal@none@1@S@(* - Part of ⌊>WordPerfect Office>⌋)@@@@1@6@@oe@26-8-2013 1000009801520@unknown@formal@none@1@S@Known versions for VAX/VMS include 5.1, 5.3 and 7.1 , year of release unknown.@@@@1@14@@oe@26-8-2013 1000009801530@unknown@formal@none@1@S@Known versions for SUN include 6.0, requiring SunOS or Solaris 2, year of release unknown.@@@@1@15@@oe@26-8-2013 1000009801540@unknown@formal@none@1@S@Known versions for IBM System/370 include 4.2, released 1988.@@@@1@9@@oe@26-8-2013 1000009801550@unknown@formal@none@1@S@Known versions for OS/2 include 5.0, released 1989.@@@@1@8@@oe@26-8-2013 1000009801560@unknown@formal@none@1@S@Known versions for the DEC Rainbow 100 include version (?), released November 1983.@@@@1@13@@oe@26-8-2013 1000009801570@unknown@formal@none@1@S@In addition, versions of WordPerfect have also been available for Apricot, Atari ST, DEC Rainbow, Tandy 2000, TI Professional, Victor 9000, and Zenith Z-100 systems, as well as around 30 flavors of unix, including AT&T, NCR, SCO Xenix, Microport Unix, DEC Ultrix, Pyramid Tech Unix, Tru64, AIX, Motorola 8000, and HP9000 and SUN 3.@@@@1@54@@oe@26-8-2013 1000009801580@unknown@formal@none@1@S@⌊=Current versions¦2=⌋@@@@1@2@@oe@26-8-2013 1000009801590@unknown@formal@none@1@S@On ⌊>January 17>⌋, ⌊>2006>⌋, Corel announced WordPerfect X3, the newest version of this office package.@@@@1@15@@oe@26-8-2013 1000009801600@unknown@formal@none@1@S@Corel is an original member of the ⌊>OASIS>⌋ Technical Committee on the ⌊>Open Document Format>⌋, and Paul Langille, a senior Corel developer, is one of the original four authors of the OpenDocument specification.@@@@1@33@@oe@26-8-2013 1000009801610@unknown@formal@none@1@S@In January 2006, subscribers to Corel's electronic newsletter were informed that WordPerfect 13 was scheduled for release later in 2006.@@@@1@20@@oe@26-8-2013 1000009801620@unknown@formal@none@1@S@The subsequent release of X3 (identified as "13" internally and in registry entries) has been met with generally positive reviews, due to new features including a unique PDF import capability, metadata removal tools, integrated search and online resources and other features.@@@@1@41@@oe@26-8-2013 1000009801630@unknown@formal@none@1@S@Version X3 was described by ⌊>CNET>⌋ in January, 2006 as a "winner", "a feature-packed productivity suite that's just as easy to use – and in many ways more innovative than – industry-goliath Microsoft Office 2003."@@@@1@35@@oe@26-8-2013 1000009801640@unknown@formal@none@1@S@CNET went on to describe X3 as "a solid upgrade for longtime users", but that "Die-hard Microsoft fans may want to wait to see what Redmond has up its sleeve with the radical changes expected within the upcoming Microsoft Office 12."@@@@1@41@@oe@26-8-2013 1000009801650@unknown@formal@none@1@S@While the notable if incremental enhancements of WordPerfect Office X3 have been well received by reviewers, a number of online forums have voiced concern about the future direction of WordPerfect, with longtime users complaining about certain usability and functionality issues that users have been asking to have fixed for the last few release versions.@@@@1@54@@oe@26-8-2013 1000009801660@unknown@formal@none@1@S@Although the released version of X3 does not support the ⌊>OOXML>⌋ or ⌊>OpenDocument>⌋ formats, a beta has been released that supports both.@@@@1@22@@oe@26-8-2013 1000009801670@unknown@formal@none@1@S@Reports surfaced late in January 2006 that Apple's ⌊>iWork>⌋ had leapfrogged WordPerfect Office as the leading alternative to Microsoft Office.@@@@1@20@@oe@26-8-2013 1000009801680@unknown@formal@none@1@S@This claim was soon debunked after industry analyst Joe Wilcox described JupiterResearch usage surveys that showed WordPerfect as the No. 2 office suite behind Microsoft Office in the consumer, small and medium businesses, and enterprise markets with a roughly 15 percent share in each market.@@@@1@45@@oe@26-8-2013 1000009801690@unknown@formal@none@1@S@In April ⌊>2008>⌋ Corel released their WordPerfect Office X4 ⌊>office suite>⌋ containing the new X4 version of WordPerfect which includes support for ⌊>PDF>⌋, ⌊>OpenDocument>⌋ and ⌊>Office Open XML>⌋.@@@@1@28@@oe@26-8-2013 1000009900010@unknown@formal@none@1@S@⌊δXHTMLδ⌋@@@@1@1@@oe@26-8-2013 1000009900020@unknown@formal@none@1@S@The ⌊∗⌊/Extensible ⌊>Hypertext>⌋ Markup Language/⌋∗⌋, or ⌊∗XHTML∗⌋, is a ⌊>markup language>⌋ that has the same depth of expression as ⌊>HTML>⌋, but also conforms to ⌊>XML>⌋ syntax.@@@@1@26@@oe@26-8-2013 1000009900030@unknown@formal@none@1@S@While HTML is an application of ⌊>Standard Generalized Markup Language>⌋ (SGML), a very flexible markup language, XHTML is an application of ⌊>XML>⌋, a more restrictive subset of SGML.@@@@1@28@@oe@26-8-2013 1000009900040@unknown@formal@none@1@S@Because they need to be ⌊>well-formed>⌋, true XHTML documents allow for automated processing to be performed using standard XML tools—unlike HTML, which requires a relatively complex, lenient, and generally custom ⌊>parser>⌋.@@@@1@31@@oe@26-8-2013 1000009900050@unknown@formal@none@1@S@XHTML can be thought of as the intersection of HTML and XML in many respects, since it is a reformulation of HTML in XML.@@@@1@24@@oe@26-8-2013 1000009900060@unknown@formal@none@1@S@XHTML 1.0 became a ⌊>World Wide Web Consortium>⌋ (W3C) ⌊>Recommendation>⌋ on ⌊>January 26>⌋, ⌊>2000>⌋.@@@@1@14@@oe@26-8-2013 1000009900070@unknown@formal@none@1@S@XHTML 1.1 became a W3C Recommendation on ⌊>May 31>⌋, ⌊>2001>⌋.@@@@1@10@@oe@26-8-2013 1000009900080@unknown@formal@none@1@S@⌊=Overview¦2=⌋@@@@1@1@@oe@26-8-2013 1000009900090@unknown@formal@none@1@S@XHTML is "a reformulation of the three HTML 4 document types as applications of XML 1.0".@@@@1@16@@oe@26-8-2013 1000009900100@unknown@formal@none@1@S@The ⌊>W3C>⌋ also continues to maintain the HTML 4.01 Recommendation and the specifications for ⌊>HTML5>⌋ and XHTML5 are being actively developed.@@@@1@21@@oe@26-8-2013 1000009900110@unknown@formal@none@1@S@In the current XHTML 1.0 Recommendation document, as published and revised to August 2002, the W3C comments that, "The XHTML family is the next step in the evolution of the Internet.@@@@1@31@@oe@26-8-2013 1000009900120@unknown@formal@none@1@S@By migrating to XHTML today, content developers can enter the XML world with all of its attendant benefits, while still remaining confident in their content's backward and future compatibility."@@@@1@29@@oe@26-8-2013 1000009900130@unknown@formal@none@1@S@⌊=Motivation¦3=⌋@@@@1@1@@oe@26-8-2013 1000009900140@unknown@formal@none@1@S@The need for a reformulated version of HTML was felt primarily because ⌊>World Wide Web>⌋ content now needs to be delivered to many devices (like ⌊>mobile device>⌋s) apart from traditional desktop ⌊>computer>⌋s, where extra resources cannot be devoted to support the additional complexity of HTML syntax.@@@@1@46@@oe@26-8-2013 1000009900150@unknown@formal@none@1@S@In practice, however, HTML-supporting browsers for such constrained devices have emerged faster than XHTML support has been added to the desktop browser with the largest market share, ⌊>Internet Explorer>⌋.@@@@1@29@@oe@26-8-2013 1000009900160@unknown@formal@none@1@S@Another goal for XHTML and XML was to reduce the demands on parsers and ⌊>user agent>⌋s in general.@@@@1@18@@oe@26-8-2013 1000009900170@unknown@formal@none@1@S@With HTML, user agents increasingly took on the burden of "correcting" errant documents.@@@@1@13@@oe@26-8-2013 1000009900180@unknown@formal@none@1@S@Instead, XML requires user agents to give a "fatal" error when encountering malformed XML.@@@@1@14@@oe@26-8-2013 1000009900190@unknown@formal@none@1@S@In theory, this allows for vendors to produce leaner browsers, without the obligation to work around author errors.@@@@1@18@@oe@26-8-2013 1000009900200@unknown@formal@none@1@S@A side effect of this behavior is that those authoring XHTML documents and testing in conformant browsers should be more readily alerted to errors that may have gone otherwise unnoticed if the browser had attempted to render or ignore the malformed markup.@@@@1@42@@oe@26-8-2013 1000009900210@unknown@formal@none@1@S@A feature XHTML inherits from its XML underpinnings is XML ⌊>namespaces>⌋.@@@@1@11@@oe@26-8-2013 1000009900220@unknown@formal@none@1@S@With namespaces, authors or communities of authors can define their own XML elements, attributes and content models to mix within XHTML documents.@@@@1@22@@oe@26-8-2013 1000009900230@unknown@formal@none@1@S@This is similar to the semantic flexibility of the ⌊◊class◊⌋ attribute in an ⌊>HTML element>⌋, but with fewer restrictions.@@@@1@19@@oe@26-8-2013 1000009900240@unknown@formal@none@1@S@Some W3C XML namespaces/schema that can be mixed with XHTML include ⌊>MathML>⌋ for semantic math markup, ⌊>Scalable Vector Graphics>⌋ for markup of vector graphics, and ⌊>RDFa>⌋ for embedding ⌊>RDF>⌋ data.@@@@1@30@@oe@26-8-2013 1000009900250@unknown@formal@none@1@S@⌊=Relationship to HTML¦3=⌋@@@@1@3@@oe@26-8-2013 1000009900260@unknown@formal@none@1@S@HTML is the ⌊>antecedent>⌋ technology to XHTML.@@@@1@7@@oe@26-8-2013 1000009900270@unknown@formal@none@1@S@The changes from HTML to first-generation XHTML 1.0 are minor and are mainly to achieve conformance with XML.@@@@1@18@@oe@26-8-2013 1000009900280@unknown@formal@none@1@S@The most important change is the requirement that the document must be ⌊>well-formed>⌋ and that all ⌊>elements>⌋ must be explicitly closed as required in XML.@@@@1@25@@oe@26-8-2013 1000009900290@unknown@formal@none@1@S@In XML, all element and attribute names are ⌊>case-sensitive>⌋, so the XHTML approach has been to define all tag names to be lowercase.@@@@1@23@@oe@26-8-2013 1000009900300@unknown@formal@none@1@S@This contrasts with some earlier established traditions which began around the time of HTML 2.0, when many used uppercase tags.@@@@1@20@@oe@26-8-2013 1000009900310@unknown@formal@none@1@S@In XHTML, all attribute values must be enclosed by quotes; either single (⌊◊'◊⌋) or double (⌊◊"◊⌋) quotes may be used.@@@@1@20@@oe@26-8-2013 1000009900320@unknown@formal@none@1@S@In contrast, this was sometimes optional in SGML-based HTML, where numeric or boolean attributes can omit quotes.@@@@1@17@@oe@26-8-2013 1000009900330@unknown@formal@none@1@S@All elements must also be explicitly closed, including empty (aka ⌊>singleton>⌋) elements such as ⌊◊img◊⌋ and ⌊◊br◊⌋.@@@@1@17@@oe@26-8-2013 1000009900340@unknown@formal@none@1@S@This can be done by adding a closing slash to the start tag, ⌊/e.g./⌋, ⌊◊<img />◊⌋ and ⌊◊<br />◊⌋.@@@@1@19@@oe@26-8-2013 1000009900350@unknown@formal@none@1@S@Attribute minimization (e.g., ⌊◊<option selected>◊⌋) is also prohibited, as the attribute ⌊◊selected◊⌋ contains no explicit value; instead this would be written as ⌊◊<option selected="selected">◊⌋.@@@@1@24@@oe@26-8-2013 1000009900360@unknown@formal@none@1@S@HTML elements which are optional in the content model will not appear in the ⌊>DOM>⌋ tree unless they are explicitly specified.@@@@1@21@@oe@26-8-2013 1000009900370@unknown@formal@none@1@S@For example, an XHTML page ⌊/must/⌋ have a ⌊◊<body>◊⌋ element, and a table will not have a ⌊◊<tbody>◊⌋ element unless the author specifies one.@@@@1@24@@oe@26-8-2013 1000009900380@unknown@formal@none@1@S@The XHTML 1.0 recommendation devotes a section to differences between HTML and XHTML..@@@@1@13@@oe@26-8-2013 1000009900390@unknown@formal@none@1@S@The WHATWG wiki similarly considers differences that arise with the use of (X)HTML5..@@@@1@13@@oe@26-8-2013 1000009900400@unknown@formal@none@1@S@Because XHTML and HTML are closely related technologies, sometimes they are written about and documented in parallel.@@@@1@17@@oe@26-8-2013 1000009900410@unknown@formal@none@1@S@In such circumstances, some authors conflate the two names by using a parenthetical notation, such as (X)HTML.@@@@1@17@@oe@26-8-2013 1000009900420@unknown@formal@none@1@S@This indicates that the documentation and principles can be considered to apply generally to both standards.@@@@1@16@@oe@26-8-2013 1000009900430@unknown@formal@none@1@S@⌊=Adoption¦3=⌋@@@@1@1@@oe@26-8-2013 1000009900440@unknown@formal@none@1@S@The similarities between HTML 4.01 and XHTML 1.0 led many web sites and content management systems to adopt the initial W3C XHTML 1.0 Recommendation.@@@@1@24@@oe@26-8-2013 1000009900450@unknown@formal@none@1@S@To aid authors in the transition, the W3C provided guidance on how to publish XHTML 1.0 documents in an HTML-compatible manner, and serve them to browsers that were not designed for XHTML.@@@@1@32@@oe@26-8-2013 1000009900460@unknown@formal@none@1@S@Such "HTML-compatible" content is sent using the HTML media type (⌊◊text/html◊⌋) rather than the official Internet media type for XHTML (⌊◊application/xhtml+xml◊⌋).@@@@1@21@@oe@26-8-2013 1000009900470@unknown@formal@none@1@S@When measuring the adoption of XHTML to that of regular HTML, therefore, it is important to distinguish whether it is media type usage or actual document contents that is being compared.@@@@1@31@@oe@26-8-2013 1000009900480@unknown@formal@none@1@S@Most web browsers have mature support for all of the possible XHTML media types.@@@@1@14@@oe@26-8-2013 1000009900490@unknown@formal@none@1@S@The notable exception is ⌊>Internet Explorer>⌋ by ⌊>Microsoft>⌋; rather than rendering ⌊◊application/xhtml+xml◊⌋ content, a dialog box invites the user to save the content to disk instead.@@@@1@26@@oe@26-8-2013 1000009900500@unknown@formal@none@1@S@Both Internet Explorer 7 (released in 2006) and the initial beta version of Internet Explorer 8 (released in March 2008) exhibit this behaviour, and it is unclear whether this will be resolved in a future release.@@@@1@36@@oe@26-8-2013 1000009900510@unknown@formal@none@1@S@Whilst this remains the case, most web developers avoid using XHTML that isn’t HTML-compatible, so advantages of XML such as namespaces, faster parsing and smaller-footprint browsers do not benefit the user.@@@@1@31@@oe@26-8-2013 1000009900520@unknown@formal@none@1@S@Microsoft developer Chris Wilson explained in 2005 that IE7’s priorities were improved security and ⌊>CSS>⌋ support, and that proper XHTML support would be difficult to graft onto IE’s compatibility-oriented HTML parser.@@@@1@31@@oe@26-8-2013 1000009900530@unknown@formal@none@1@S@Recently, notable developers have begun to question why Web authors ever made the leap into authoring in XHTML.@@@@1@18@@oe@26-8-2013 1000009900540@unknown@formal@none@1@S@In October 2006, HTML inventor and W3C chair ⌊>Tim Berners-Lee>⌋, explaining the motivation for the resumption of HTML (not XHTML) development, posted in his blog: "The attempt to get the world to switch to XML, including quotes around attribute values and slashes in empty tags and namespaces all at once didn't work.@@@@1@52@@oe@26-8-2013 1000009900550@unknown@formal@none@1@S@The large HTML-generating public did not move, largely because the browsers didn't complain."@@@@1@13@@oe@26-8-2013 1000009900560@unknown@formal@none@1@S@⌊=Versions of XHTML¦2=⌋@@@@1@3@@oe@26-8-2013 1000009900570@unknown@formal@none@1@S@⌊=XHTML 1.0¦3=⌋@@@@1@2@@oe@26-8-2013 1000009900580@unknown@formal@none@1@S@December 1998 saw the publication of a W3C Working Draft entitled ⌊/Reformulating HTML in XML/⌋.@@@@1@15@@oe@26-8-2013 1000009900590@unknown@formal@none@1@S@This introduced Voyager, the codename for a new markup language based on HTML 4 but adhering to the stricter syntax rules of XML.@@@@1@23@@oe@26-8-2013 1000009900600@unknown@formal@none@1@S@By February 1999 the specification had changed name to ⌊/XHTML™ 1.0: The Extensible HyperText Markup Language/⌋, and in January 2000 it was officially adopted as a W3C Recommendation.@@@@1@28@@oe@26-8-2013 1000009900610@unknown@formal@none@1@S@There are three formal ⌊>DTDs>⌋ for XHTML 1.0, corresponding to the three different versions of HTML 4.01:@@@@1@17@@oe@26-8-2013 1000009900620@unknown@formal@none@1@S@⌊•⌊#⌊∗XHTML 1.0 Strict∗⌋ is the equivalent to strict HTML 4.01, and includes elements and attributes that have not been marked deprecated in the HTML 4.01 specification.#⌋@@@@1@26@@oe@26-8-2013 1000009900630@unknown@formal@none@1@S@⌊#⌊∗XHTML 1.0 Transitional∗⌋ is the equivalent of HTML 4.01 Transitional, and includes the presentational elements (such as ⌊◊center◊⌋, ⌊◊font◊⌋ and ⌊◊strike◊⌋) excluded from the strict version.#⌋@@@@1@26@@oe@26-8-2013 1000009900640@unknown@formal@none@1@S@⌊#⌊∗XHTML 1.0 Frameset∗⌋ is the equivalent of HTML 4.01 Frameset, and allows for the definition of ⌊>frameset documents>⌋—a common Web feature in the late 1990s.#⌋•⌋@@@@1@25@@oe@26-8-2013 1000009900650@unknown@formal@none@1@S@The second edition of XHTML 1.0 became a W3C Recommendation in August 2002.@@@@1@13@@oe@26-8-2013 1000009900660@unknown@formal@none@1@S@⌊=Modularization of XHTML¦3=⌋@@@@1@3@@oe@26-8-2013 1000009900670@unknown@formal@none@1@S@The initial draft of ⌊/Modularization of XHTML/⌋ became available in April 1999, and reached Recommendation status in April 2001.@@@@1@19@@oe@26-8-2013 1000009900680@unknown@formal@none@1@S@⌊>Modularization>⌋ provides an abstract collection of components through which XHTML can be subsetted and extended.@@@@1@15@@oe@26-8-2013 1000009900690@unknown@formal@none@1@S@The feature is intended to help XHTML extend it’s reach onto emerging platforms, such as mobile devices and Web-enabled televisions.@@@@1@20@@oe@26-8-2013 1000009900700@unknown@formal@none@1@S@The first XHTML Family Markup Languages to be developed with this technique were XHTML 1.1 and XHTML Basic 1.0.@@@@1@19@@oe@26-8-2013 1000009900710@unknown@formal@none@1@S@Another example is XHTML-Print (W3C Recommendation, September 2006), a language designed for printing from mobile devices to low-cost printers.@@@@1@19@@oe@26-8-2013 1000009900720@unknown@formal@none@1@S@In 2008 ⌊/Modularization of XHTML/⌋ is expected to be superseded by ⌊/XHTML Modularization 1.1/⌋, which adds an ⌊>XML Schema>⌋ implementation.@@@@1@20@@oe@26-8-2013 1000009900730@unknown@formal@none@1@S@⌊=XHTML 1.1—Module-based XHTML¦3=⌋@@@@1@3@@oe@26-8-2013 1000009900740@unknown@formal@none@1@S@XHTML 1.1 evolved out of the work surrounding the initial ⌊/Modularization of XHTML/⌋ specification.@@@@1@14@@oe@26-8-2013 1000009900750@unknown@formal@none@1@S@The W3C released a first draft in September 1999; Recommendation status was reached in May 2001.@@@@1@16@@oe@26-8-2013 1000009900760@unknown@formal@none@1@S@The modules combined within XHTML 1.1 effectively recreate XHTML 1.0 Strict, with the addition of ⌊>ruby annotation>⌋ elements (⌊◊ruby◊⌋, ⌊◊rbc◊⌋, ⌊◊rtc◊⌋, ⌊◊rb◊⌋, ⌊◊rt◊⌋ and ⌊◊rp◊⌋) to better support East-Asian languages.@@@@1@30@@oe@26-8-2013 1000009900770@unknown@formal@none@1@S@Other changes include removal of the ⌊◊lang◊⌋ attribute (in favour of ⌊◊xml:lang◊⌋), and removal of the ⌊◊name◊⌋ attribute from the ⌊◊a◊⌋ and ⌊◊map◊⌋ elements.@@@@1@24@@oe@26-8-2013 1000009900780@unknown@formal@none@1@S@Although XHTML 1.1 is largely compatible with XHTML 1.0 and HTML 4, in August 2002 the W3C issued a formal Note advising that it should not be transmitted with the HTML media type.@@@@1@33@@oe@26-8-2013 1000009900790@unknown@formal@none@1@S@With limited browser support for the alternate ⌊◊application/xhtml+xml◊⌋ media type, XHTML 1.1 has so far proven unable to gain widespread use.@@@@1@21@@oe@26-8-2013 1000009900800@unknown@formal@none@1@S@XHTML 1.1 Second Edition is expected in the third quarter of 2008.@@@@1@12@@oe@26-8-2013 1000009900810@unknown@formal@none@1@S@⌊=XHTML Basic and XHTML-MP¦3=⌋@@@@1@4@@oe@26-8-2013 1000009900820@unknown@formal@none@1@S@To support constrained devices, ⌊/⌊>XHTML Basic>⌋/⌋ was created by the W3C; it reached Recommendation status in December 2000.@@@@1@18@@oe@26-8-2013 1000009900830@unknown@formal@none@1@S@XHTML Basic 1.0 is the most restrictive version of XHTML, providing a minimal set of features that even the most limited devices can be expected to support.@@@@1@27@@oe@26-8-2013 1000009900840@unknown@formal@none@1@S@The ⌊>Open Mobile Alliance>⌋ and it’s predecessor the WAP Forum released three specifications between 2001 and 2006 that extended XHTML Basic 1.0.@@@@1@22@@oe@26-8-2013 1000009900850@unknown@formal@none@1@S@Known as ⌊>XHTML Mobile Profile>⌋ or XHTML-MP, they were strongly focussed on uniting the differing markup languages used on ⌊>mobile handsets>⌋ at the time.@@@@1@24@@oe@26-8-2013 1000009900860@unknown@formal@none@1@S@All provide richer form controls than XHTML Basic 1.0, along with varying levels of scripting support.@@@@1@16@@oe@26-8-2013 1000009900870@unknown@formal@none@1@S@⌊/XHTML Basic 1.1/⌋ became a W3C Proposed Recommendation in June 2008, superseding XHTML-MP 1.2.@@@@1@14@@oe@26-8-2013 1000009900880@unknown@formal@none@1@S@XHTML Basic 1.1 is almost but not quite a subset of regular XHTML 1.1.@@@@1@14@@oe@26-8-2013 1000009900890@unknown@formal@none@1@S@The most notable addition over XHTML 1.1 is the ⌊◊inputmode◊⌋ attribute—also found in XHTML-MP 1.2—which provides hints to help browsers improve form entry.@@@@1@23@@oe@26-8-2013 1000009900900@unknown@formal@none@1@S@⌊=XHTML 1.2¦3=⌋@@@@1@2@@oe@26-8-2013 1000009900910@unknown@formal@none@1@S@The XHTML 2 Working Group is considering the creation a new language based on XHTML 1.1.@@@@1@16@@oe@26-8-2013 1000009900920@unknown@formal@none@1@S@If XHTML 1.2 is created, it will include ⌊>WAI-ARIA>⌋ and ⌊◊role◊⌋ attributes to better support accessible web applications, and improved ⌊>Semantic Web>⌋ support through ⌊>RDFa>⌋.@@@@1@25@@oe@26-8-2013 1000009900930@unknown@formal@none@1@S@The ⌊◊inputmode◊⌋ attribute from XHTML Basic 1.1, along with the ⌊◊target◊⌋ attribute (for specifying ⌊>frame>⌋ targets) may also be present.@@@@1@20@@oe@26-8-2013 1000009900940@unknown@formal@none@1@S@⌊=XHTML 2.0¦3=⌋@@@@1@2@@oe@26-8-2013 1000009900950@unknown@formal@none@1@S@Between August 2002 and July 2006 the W3C released the first eight Working Drafts of XHTML 2.0, a new version of XHTML able to make a clean break from the past by discarding the requirement of backward compatibility.@@@@1@38@@oe@26-8-2013 1000009900960@unknown@formal@none@1@S@This lack of compatibility with XHTML 1.x and HTML 4 caused some early controversy in the web developer community.@@@@1@19@@oe@26-8-2013 1000009900970@unknown@formal@none@1@S@Some parts of the language (such as the ⌊◊role◊⌋ and RDFa attributes) were subsequently split out of the specification and worked on as separate modules, partially to help make the transition from XHTML 1.x to XHTML 2.0 smoother.@@@@1@38@@oe@26-8-2013 1000009900980@unknown@formal@none@1@S@A ninth draft of XHTML 2.0 is expected to appear in 2008.@@@@1@12@@oe@26-8-2013 1000009900990@unknown@formal@none@1@S@New features introduced by XHTML 2.0 include:@@@@1@7@@oe@26-8-2013 1000009901000@unknown@formal@none@1@S@⌊•⌊#HTML forms will be replaced by ⌊>XForms>⌋, an XML-based user input specification allowing forms to be displayed appropriately for different rendering devices.#⌋@@@@1@22@@oe@26-8-2013 1000009901010@unknown@formal@none@1@S@⌊#HTML frames will be replaced by ⌊>XFrames>⌋.#⌋@@@@1@7@@oe@26-8-2013 1000009901020@unknown@formal@none@1@S@⌊#The ⌊>DOM Events>⌋ will be replaced by ⌊>XML Events>⌋, which uses the XML ⌊>Document Object Model>⌋.#⌋@@@@1@16@@oe@26-8-2013 1000009901030@unknown@formal@none@1@S@⌊#A new list element type, the ⌊◊nl◊⌋ element type, will be included to specifically designate a list as a navigation list.@@@@1@21@@oe@26-8-2013 1000009901040@unknown@formal@none@1@S@This will be useful in creating nested menus, which are currently created by a wide variety of means like nested unordered lists or nested definition lists.#⌋@@@@1@26@@oe@26-8-2013 1000009901050@unknown@formal@none@1@S@⌊#Any element will be able to act as a ⌊>hyperlink>⌋, e.g., ⌊◊<li href="articles.html">Articles</li>◊⌋, similar to ⌊>XLink>⌋.@@@@1@16@@oe@26-8-2013 1000009901060@unknown@formal@none@1@S@However, XLink itself is not compatible with XHTML due to design differences.#⌋@@@@1@12@@oe@26-8-2013 1000009901070@unknown@formal@none@1@S@⌊#Any element will be able to reference alternative media with the ⌊◊src◊⌋ attribute, e.g., ⌊◊<p src="lbridge.jpg" type="image/jpeg">London Bridge</p>◊⌋ is the same as ⌊◊<object src="lbridge.jpg" type="image/jpeg"><p>London Bridge</p></object>◊⌋.#⌋@@@@1@26@@oe@26-8-2013 1000009901080@unknown@formal@none@1@S@⌊#The ⌊◊alt◊⌋ attribute of the ⌊◊img◊⌋ element has been removed: alternative text will be given in the content of the ⌊◊img◊⌋ element, much like the ⌊◊object◊⌋ element, e.g., ⌊◊<img src="hms_audacious.jpg">HMS <em>Audacious</em></img>◊⌋.#⌋@@@@1@31@@oe@26-8-2013 1000009901090@unknown@formal@none@1@S@⌊#A single heading element (⌊◊h◊⌋) will be added.@@@@1@8@@oe@26-8-2013 1000009901100@unknown@formal@none@1@S@The level of these headings are determined by the depth of the nesting.@@@@1@13@@oe@26-8-2013 1000009901110@unknown@formal@none@1@S@This allows the use of headings to be infinite, rather than limiting use to six levels deep.#⌋@@@@1@17@@oe@26-8-2013 1000009901120@unknown@formal@none@1@S@⌊#The remaining presentational elements ⌊◊i◊⌋, ⌊◊b◊⌋ and ⌊◊tt◊⌋, still allowed in XHTML 1.x (even Strict), will be absent from XHTML 2.0.@@@@1@21@@oe@26-8-2013 1000009901130@unknown@formal@none@1@S@The only somewhat presentational elements remaining will be ⌊◊sup◊⌋ and ⌊◊sub◊⌋ for superscript and subscript respectively, because they have significant non-presentational uses and are required by certain languages.@@@@1@28@@oe@26-8-2013 1000009901140@unknown@formal@none@1@S@All other tags are meant to be ⌊>semantic>⌋ instead (e.g. ⌊◊<strong>◊⌋ for ⌊∗strong or bolded∗⌋ text) while allowing the user agent to control the presentation of elements via CSS.#⌋@@@@1@29@@oe@26-8-2013 1000009901150@unknown@formal@none@1@S@⌊#The addition of RDF triple with the ⌊◊property◊⌋ and ⌊◊about◊⌋ attributes to facilitate the conversion from XHTML to RDF/XML.#⌋•⌋@@@@1@19@@oe@26-8-2013 1000009901160@unknown@formal@none@1@S@⌊=HTML 5—Vocabulary and APIs for HTML and XHTML¦3=⌋@@@@1@8@@oe@26-8-2013 1000009901170@unknown@formal@none@1@S@⌊>HTML 5>⌋ initially grew independently of the W3C, through a loose group of browser manufacturers and other interested parties calling themselves the ⌊>WHATWG>⌋, or Web Hypertext Application Technology Working Group.@@@@1@30@@oe@26-8-2013 1000009901180@unknown@formal@none@1@S@The WHATWG announced the existence of an open mailing list in June 2004, along with a website bearing the strapline “Maintaining and evolving HTML since 2004.”@@@@1@26@@oe@26-8-2013 1000009901190@unknown@formal@none@1@S@The key motive of the group was to create a platform for dynamic web applications; they considered XHTML 2.0 to be too document-centric, and not suitable for the creation of forum sites or online shops.@@@@1@35@@oe@26-8-2013 1000009901200@unknown@formal@none@1@S@In April 2007, the Mozilla Foundation and Opera Software joined Apple in requesting that the newly rechartered HTML Working Group of the W3C adopt the work, under the name of HTML 5.@@@@1@32@@oe@26-8-2013 1000009901210@unknown@formal@none@1@S@The group resolved to do this the following month, and the First Public Working Draft of HTML 5 was issued by the W3C in January 2008.@@@@1@26@@oe@26-8-2013 1000009901220@unknown@formal@none@1@S@The most recent W3C Working Draft was published in June 2008.@@@@1@11@@oe@26-8-2013 1000009901230@unknown@formal@none@1@S@HTML 5 has both a regular ⌊◊text/html◊⌋ serialization and an XML serialization, which is known as XHTML 5.@@@@1@18@@oe@26-8-2013 1000009901240@unknown@formal@none@1@S@In addition to the markup language, the specification includes a number of ⌊>application programming interfaces>⌋.@@@@1@15@@oe@26-8-2013 1000009901250@unknown@formal@none@1@S@The ⌊>Document Object Model>⌋ is extended with APIs for editing, drag-and-drop, data storage and network communication.@@@@1@16@@oe@26-8-2013 1000009901260@unknown@formal@none@1@S@The language can be considered more compatible with HTML 4 and XHTML 1.x than XHTML 2.0, due to the decision to keep the existing HTML form elements and events model.@@@@1@30@@oe@26-8-2013 1000009901270@unknown@formal@none@1@S@It adds many new elements not found in XHTML 1.x, however, such as ⌊◊section◊⌋ and ⌊◊aside◊⌋.@@@@1@16@@oe@26-8-2013 1000009901280@unknown@formal@none@1@S@(The XHTML 1.2 equivalent of these structural elements would be ⌊◊<div role="region">◊⌋ and ⌊◊<div role="complementary">◊⌋.)@@@@1@15@@oe@26-8-2013 1000009901290@unknown@formal@none@1@S@The specification is expected to add WAI-ARIA support in a future draft.@@@@1@12@@oe@26-8-2013 1000009901300@unknown@formal@none@1@S@There is currently no indication as to whether HTML 5 will support RDFa, or be limited just to ⌊>microformats>⌋.@@@@1@19@@oe@26-8-2013 1000009901310@unknown@formal@none@1@S@⌊=Valid XHTML documents¦2=⌋@@@@1@3@@oe@26-8-2013 1000009901320@unknown@formal@none@1@S@An XHTML document that conforms to an XHTML specification is said to be ⌊/valid/⌋.@@@@1@14@@oe@26-8-2013 1000009901330@unknown@formal@none@1@S@Validity assures consistency in document code, which in turn eases processing, but does not necessarily ensure consistent rendering by browsers.@@@@1@20@@oe@26-8-2013 1000009901340@unknown@formal@none@1@S@A document can be checked for validity with the ⌊>W3C Markup Validation Service>⌋.@@@@1@13@@oe@26-8-2013 1000009901350@unknown@formal@none@1@S@In practice, many web development programs such as ⌊>Dreamweaver>⌋ provide code validation based on the ⌊>W3C>⌋ standards.@@@@1@17@@oe@26-8-2013 1000009901360@unknown@formal@none@1@S@⌊=DOCTYPEs¦3=⌋@@@@1@1@@oe@26-8-2013 1000009901370@unknown@formal@none@1@S@In order to validate an XHTML document, a ⌊>Document Type Declaration>⌋, or ⌊/DOCTYPE/⌋, may be used.@@@@1@16@@oe@26-8-2013 1000009901380@unknown@formal@none@1@S@A DOCTYPE declares to the browser which ⌊>Document Type Definition>⌋ (DTD) the document conforms to.@@@@1@15@@oe@26-8-2013 1000009901390@unknown@formal@none@1@S@A Document Type Declaration should be placed before the ⌊>root element>⌋.@@@@1@11@@oe@26-8-2013 1000009901400@unknown@formal@none@1@S@The ⌊>system identifier>⌋ part of the DOCTYPE, which in these examples is the ⌊>URL>⌋ that begins with ⌊/⌊>http://'',>⌋ need only point to a copy of the DTD to use if the validator cannot locate one based on the ⌊>public identifier>⌋ (the other quoted string).@@@@1@44@@oe@26-8-2013 1000009901410@unknown@formal@none@1@S@It does not need to be the specific URL that is in these examples; in fact, authors are encouraged to use local copies of the DTD files when possible.@@@@1@29@@oe@26-8-2013 1000009901420@unknown@formal@none@1@S@The public identifier, however, must be character-for-character the same as in the examples./⌋@@@@1@13@@oe@26-8-2013 1000009901430@unknown@formal@none@1@S@These are the most common XHTML Document Type Declarations:@@@@1@9@@oe@26-8-2013 1000009901440@unknown@formal@none@1@S@⌊:XHTML 1.0 Strict:⌋@@@@1@3@@oe@26-8-2013 1000009901450@unknown@formal@none@1@S@⌊⇥⌊◊<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">◊⌋⇥⌋@@@@1@7@@oe@26-8-2013 1000009901460@unknown@formal@none@1@S@⌊:XHTML 1.0 Transitional:⌋@@@@1@3@@oe@26-8-2013 1000009901470@unknown@formal@none@1@S@⌊⇥⌊◊<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">◊⌋⇥⌋@@@@1@7@@oe@26-8-2013 1000009901480@unknown@formal@none@1@S@⌊:XHTML 1.0 Frameset:⌋@@@@1@3@@oe@26-8-2013 1000009901490@unknown@formal@none@1@S@⌊⇥⌊◊<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">◊⌋⇥⌋@@@@1@7@@oe@26-8-2013 1000009901500@unknown@formal@none@1@S@⌊:XHTML 1.1:⌋@@@@1@2@@oe@26-8-2013 1000009901510@unknown@formal@none@1@S@⌊⇥⌊◊<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN""http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">◊⌋⇥⌋@@@@1@6@@oe@26-8-2013 1000009901520@unknown@formal@none@1@S@⌊:HTML 5:⌋@@@@1@2@@oe@26-8-2013 1000009901530@unknown@formal@none@1@S@HTML5 does not require a doctype, and HTML 5 validation is not DTD-based.@@@@1@13@@oe@26-8-2013 1000009901540@unknown@formal@none@1@S@⌊:XHTML 2.0:⌋@@@@1@2@@oe@26-8-2013 1000009901550@unknown@formal@none@1@S@XHTML 2.0, ⌊>As of April 2008>⌋, is in a draft phase.@@@@1@11@@oe@26-8-2013 1000009901560@unknown@formal@none@1@S@If an XHTML 2.0 Recommendation is published with the same document type declaration as in the current Working Draft, the declaration will appear as:@@@@1@24@@oe@26-8-2013 1000009901570@unknown@formal@none@1@S@⌊⇥⌊◊<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 2.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml2.dtd">◊⌋⇥⌋@@@@1@7@@oe@26-8-2013 1000009901580@unknown@formal@none@1@S@A placeholder DTD schema exists at the corresponding URI, though it currently only includes the character reference entities from previous recommendations.@@@@1@21@@oe@26-8-2013 1000009901590@unknown@formal@none@1@S@XHTML 2 contemplates both a ⌊◊version◊⌋ attribute and an ⌊◊xsi:schemalocation◊⌋ attribute on the root HTML element that could possibly serve as a substitute for any DOCTYPE declaration.@@@@1@27@@oe@26-8-2013 1000009901600@unknown@formal@none@1@S@⌊=XML namespaces and schemas¦4=⌋@@@@1@4@@oe@26-8-2013 1000009901610@unknown@formal@none@1@S@In addition to the DOCTYPE, all XHTML elements must be in the appropriate ⌊>XML namespace>⌋ for the version being used.@@@@1@20@@oe@26-8-2013 1000009901620@unknown@formal@none@1@S@This is usually done by declaring a default namespace on the root element using ⌊◊xmlns="namespace"◊⌋ as in the example below.@@@@1@20@@oe@26-8-2013 1000009901630@unknown@formal@none@1@S@For XHTML 1.0, XHTML 1.1 and HTML5, this is@@@@1@9@@oe@26-8-2013 1000009901640@unknown@formal@none@1@S@⌊⇥⌊◊<html xmlns="http://www.w3.org/1999/xhtml">◊⌋⇥⌋@@@@1@2@@oe@26-8-2013 1000009901650@unknown@formal@none@1@S@XHTML 2.0 requires both a namespace and an ⌊>XML Schema>⌋ instance declaration.@@@@1@12@@oe@26-8-2013 1000009901660@unknown@formal@none@1@S@These might be declared as@@@@1@5@@oe@26-8-2013 1000009901670@unknown@formal@none@1@S@⌊⇥⌊◊<html xmlns="http://www.w3.org/2002/06/xhtml2/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.w3.org/2002/06/xhtml2/ http://www.w3.org/MarkUp/SCHEMA/xhtml2.xsd">◊⌋⇥⌋@@@@1@4@@oe@26-8-2013 1000009901680@unknown@formal@none@1@S@This example for XHTML 2.0 also demonstrates the use of multiple namespaces within a document.@@@@1@15@@oe@26-8-2013 1000009901690@unknown@formal@none@1@S@The first ⌊◊xmlns◊⌋ default namespace declaration indicates that elements and attributes whose names have no XML namespace prefix fall within the XHTML 2.0 namespace.@@@@1@24@@oe@26-8-2013 1000009901700@unknown@formal@none@1@S@The second namespace prefix declaration ⌊◊xmlns:xsi◊⌋ indicates that any elements or attributes prefixed with the ⌊◊xsi:◊⌋ refer to the XMLSchema-Instance namespace.@@@@1@21@@oe@26-8-2013 1000009901710@unknown@formal@none@1@S@Through this namespace mechanism XML documents allow the use of a mixture of elements and attributes taken from various XML vocabularies while avoiding the potential for clashes of naming between items from independently developed vocabularies.@@@@1@35@@oe@26-8-2013 1000009901720@unknown@formal@none@1@S@Similar to the case of DOCTYPE above, the actual URL to the ⌊>XML Schema>⌋ file can be changed, as long as the ⌊>Universal Resource Identifier>⌋ (URI) before it (which indicates the XHTML 2.0 namespace) remains the same.@@@@1@37@@oe@26-8-2013 1000009901730@unknown@formal@none@1@S@The namespace URI is intended to be a persistent and universally unique identifier for the particular version of the specification.@@@@1@20@@oe@26-8-2013 1000009901740@unknown@formal@none@1@S@If treated as a URL, the actual content located at the site is of no significance.@@@@1@16@@oe@26-8-2013 1000009901750@unknown@formal@none@1@S@⌊=XML Declaration¦4=⌋@@@@1@2@@oe@26-8-2013 1000009901760@unknown@formal@none@1@S@A ⌊>character encoding>⌋ may be specified at the beginning of an XHTML document in the XML declaration when the document is served using the ⌊◊application/xhtml+xml◊⌋ MIME type.@@@@1@27@@oe@26-8-2013 1000009901770@unknown@formal@none@1@S@(If an XML document lacks encoding specification, an XML parser assumes that the encoding is ⌊>UTF-8>⌋ or ⌊>UTF-16>⌋, unless the encoding has already been determined by a higher protocol.)@@@@1@29@@oe@26-8-2013 1000009901780@unknown@formal@none@1@S@For example:@@@@1@2@@oe@26-8-2013 1000009901790@unknown@formal@none@1@S@⌊⇥⌊◊<?xml version="1.0" encoding="UTF-8"?>◊⌋⇥⌋@@@@1@3@@oe@26-8-2013 1000009901800@unknown@formal@none@1@S@The declaration may be optionally omitted because it declares as its encoding the default encoding.@@@@1@15@@oe@26-8-2013 1000009901810@unknown@formal@none@1@S@However, if the document instead makes use of XML 1.1 or another character encoding, a declaration is necessary.@@@@1@18@@oe@26-8-2013 1000009901820@unknown@formal@none@1@S@⌊>Internet Explorer>⌋ prior to version 7 enters ⌊>quirks mode>⌋ if it encounters an XML declaration in a document served as ⌊◊text/html◊⌋.@@@@1@21@@oe@26-8-2013 1000009901830@unknown@formal@none@1@S@⌊=Common errors¦3=⌋@@@@1@2@@oe@26-8-2013 1000009901840@unknown@formal@none@1@S@Some of the most common errors in the usage of XHTML are:@@@@1@12@@oe@26-8-2013 1000009901850@unknown@formal@none@1@S@⌊•⌊#Failing to realize that documents won’t be treated as XHTML unless they are served with an appropriate XML ⌊>MIME type>⌋#⌋@@@@1@20@@oe@26-8-2013 1000009901860@unknown@formal@none@1@S@⌊#Not closing empty elements (elements without closing tags in HTML4)@@@@1@10@@oe@26-8-2013 1000009901870@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<br>◊⌋#⌋@@@@1@2@@oe@26-8-2013 1000009901880@unknown@formal@none@1@S@⌊#Correct: ⌊◊<br />◊⌋@@@@1@3@@oe@26-8-2013 1000009901890@unknown@formal@none@1@S@Note that any of these are acceptable in XHTML: ⌊◊<br></br>◊⌋, ⌊◊<br/>◊⌋ and ⌊◊<br />◊⌋.@@@@1@13@@oe@26-8-2013 1000009901900@unknown@formal@none@1@S@Older HTML-only browsers interpreting it as HTML will generally accept ⌊◊<br>◊⌋ and ⌊◊<br />◊⌋.#⌋•⌋#⌋@@@@1@13@@oe@26-8-2013 1000009901910@unknown@formal@none@1@S@⌊#Not closing non-empty elements@@@@1@4@@oe@26-8-2013 1000009901920@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<p>This is a paragraph.<p>This is another paragraph.◊⌋#⌋@@@@1@8@@oe@26-8-2013 1000009901930@unknown@formal@none@1@S@⌊#Correct: ⌊◊<p>This is a paragraph.</p><p>This is another paragraph.</p>◊⌋#⌋•⌋#⌋@@@@1@8@@oe@26-8-2013 1000009901940@unknown@formal@none@1@S@⌊#Improperly nesting elements (Note that this would also be invalid in ⌊>HTML>⌋)@@@@1@12@@oe@26-8-2013 1000009901950@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<em><strong>This is some text.</em></strong>◊⌋#⌋@@@@1@5@@oe@26-8-2013 1000009901960@unknown@formal@none@1@S@⌊#Correct: ⌊◊<em><strong>This is some text.</strong></em>◊⌋#⌋•⌋#⌋@@@@1@5@@oe@26-8-2013 1000009901970@unknown@formal@none@1@S@⌊#Not putting quotation marks around attribute values@@@@1@7@@oe@26-8-2013 1000009901980@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<td rowspan=3>◊⌋#⌋@@@@1@3@@oe@26-8-2013 1000009901990@unknown@formal@none@1@S@⌊#Correct: ⌊◊<td rowspan="3">◊⌋#⌋@@@@1@3@@oe@26-8-2013 1000009902000@unknown@formal@none@1@S@⌊#Correct: ⌊◊<td rowspan='3'>◊⌋#⌋•⌋#⌋@@@@1@3@@oe@26-8-2013 1000009902010@unknown@formal@none@1@S@⌊#Using the ampersand character outside of entities@@@@1@7@@oe@26-8-2013 1000009902020@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<title>Cars & Trucks</title>◊⌋#⌋@@@@1@4@@oe@26-8-2013 1000009902030@unknown@formal@none@1@S@⌊#Correct: ⌊◊<title>Cars & Trucks</title>◊⌋#⌋•⌋#⌋@@@@1@4@@oe@26-8-2013 1000009902040@unknown@formal@none@1@S@⌊#Using the ampersand outside of entities in ⌊>URL>⌋s (Note that this would also be invalid in ⌊>HTML>⌋)@@@@1@17@@oe@26-8-2013 1000009902050@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<a href="index.php?page=news&style=5">News</a>◊⌋#⌋@@@@1@3@@oe@26-8-2013 1000009902060@unknown@formal@none@1@S@⌊#Correct: ⌊◊<a href="index.php?page=news&style=5">News</a>◊⌋#⌋•⌋#⌋@@@@1@3@@oe@26-8-2013 1000009902070@unknown@formal@none@1@S@⌊#Failing to recognize that XHTML elements and attributes are case sensitive@@@@1@11@@oe@26-8-2013 1000009902080@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<BODY><P ID="ONE">The Best Page Ever</P></BODY>◊⌋#⌋@@@@1@6@@oe@26-8-2013 1000009902090@unknown@formal@none@1@S@⌊#Correct: ⌊◊<body><p id="ONE">The Best Page Ever</p></body>◊⌋#⌋•⌋#⌋@@@@1@6@@oe@26-8-2013 1000009902100@unknown@formal@none@1@S@⌊#Using attribute minimization@@@@1@3@@oe@26-8-2013 1000009902110@unknown@formal@none@1@S@⌊•⌊#Incorrect: ⌊◊<textarea readonly>READ-ONLY</textarea>◊⌋#⌋@@@@1@3@@oe@26-8-2013 1000009902120@unknown@formal@none@1@S@⌊#Correct: ⌊◊<textarea readonly="readonly">READ-ONLY</textarea>◊⌋#⌋•⌋#⌋@@@@1@3@@oe@26-8-2013 1000009902130@unknown@formal@none@1@S@⌊#Mis-using CDATA, script-comments and xml-comments when embedding scripts and stylesheets.@@@@1@10@@oe@26-8-2013 1000009902140@unknown@formal@none@1@S@⌊•⌊#This problem can be avoided altogether by putting all script and stylesheet information into separate files and referring to them as follows in the XHTML ⌊◊head◊⌋ element.#⌋•⌋#⌋•⌋@@@@1@27@@oe@26-8-2013 1000009902150@unknown@formal@none@1@S@⌊π<link rel="stylesheet" href="/style/screen.css" type="text/css" /> <script type="text/javascript" src="/script/site.js"></script>π⌋@@@@1@8@@oe@26-8-2013 1000009902160@unknown@formal@none@1@S@⌊⇥⌊⇥Note: The format ⌊◊<script …></script>◊⌋, rather than the more concise ⌊◊<script … />◊⌋, is required for HTML compatibility when served as MIME type ⌊◊text/html◊⌋.⇥⌋⇥⌋@@@@1@24@@oe@26-8-2013 1000009902170@unknown@formal@none@1@S@⌊•⌊#⌊•⌊#If an author chooses to include script or style data inline within an XHTML document, different approaches are recommended depending whether the author intends to serve the page as ⌊◊application/xhtml+xml◊⌋ and target only fully conformant browsers, or serve the page as ⌊◊text/html◊⌋ and try to obtain usability in Internet Explorer 6 and other non-conformant browsers.#⌋•⌋#⌋•⌋@@@@1@55@@oe@26-8-2013 1000009902180@unknown@formal@none@1@S@⌊=Backward compatibility¦2=⌋@@@@1@2@@oe@26-8-2013 1000009902190@unknown@formal@none@1@S@XHTML 1.x documents are mostly backward compatible with HTML 4 user agents when the appropriate guidelines are followed.@@@@1@18@@oe@26-8-2013 1000009902200@unknown@formal@none@1@S@XHTML 1.1 is essentially compatible, although the elements for ⌊>ruby annotiation>⌋ are not part of the HTML 4 specification and thus generally ignored by HTML 4 browsers.@@@@1@27@@oe@26-8-2013 1000009902210@unknown@formal@none@1@S@Later XHTML 1.x modules such as those for the ⌊◊role◊⌋ attribute, ⌊>RDFa>⌋ and ⌊>WAI-ARIA>⌋ degrade gracefully in a similar manner.@@@@1@20@@oe@26-8-2013 1000009902220@unknown@formal@none@1@S@HTML 5 and XHTML 2 are significantly less compatible, although this can be mitigated to some degree through the use of scripting.@@@@1@22@@oe@26-8-2013 1000009902230@unknown@formal@none@1@S@(This can be simple one-liners, such as the use of “⌊◊document.createElement()◊⌋” to register a new HTML element within Internet Explorer, or complete JavaScript frameworks, such as the ⌊>FormFaces>⌋ implementation of ⌊>XForms>⌋.)@@@@1@31@@oe@26-8-2013 1000009902240@unknown@formal@none@1@S@⌊=Examples¦3=⌋@@@@1@1@@oe@26-8-2013 1000009902250@unknown@formal@none@1@S@The followings are examples of XHTML 1.0 Strict.@@@@1@8@@oe@26-8-2013 1000009902260@unknown@formal@none@1@S@Both of them have the same visual output.@@@@1@8@@oe@26-8-2013 1000009902270@unknown@formal@none@1@S@The former one follows the ⌊> HTML Compatibility Guidelines>⌋ in Appendix C of the XHTML 1.0 Specification while the latter one breaks backward compatibility but provides cleaner codes.@@@@1@28@@oe@26-8-2013 1000009902280@unknown@formal@none@1@S@Example 1.@@@@1@2@@oe@26-8-2013 1000009902290@unknown@formal@none@1@S@Example 2.@@@@1@2@@oe@26-8-2013 1000009902300@unknown@formal@none@1@S@Notes:@@@@1@1@@oe@26-8-2013 1000009902310@unknown@formal@none@1@S@⌊•⌊#For further information on the media type recommendation, please refer to ⌊> XHTML Media Types>⌋, a W3C Note issued on 2002-08-01.#⌋@@@@1@21@@oe@26-8-2013 1000009902320@unknown@formal@none@1@S@⌊#The "loadpdf" function is actually a workaround for Internet Explorer.@@@@1@10@@oe@26-8-2013 1000009902330@unknown@formal@none@1@S@It can be replaced by adding ⌊◊<param name="src" value="http://www.w3.org/TR/xhtml1/xhtml1.pdf" />◊⌋ within ⌊◊<object>◊⌋.#⌋@@@@1@12@@oe@26-8-2013 1000009902340@unknown@formal@none@1@S@⌊#The ⌊◊img◊⌋ element does not get a ⌊◊name◊⌋ attribute in the ⌊> XHTML 1.0 Strict DTD>⌋.@@@@1@16@@oe@26-8-2013 1000009902350@unknown@formal@none@1@S@Use ⌊◊id◊⌋ instead.#⌋•⌋@@@@1@3@@oe@26-8-2013 1000010000010@unknown@formal@none@1@S@⌊δXMLδ⌋@@@@1@1@@oe@26-8-2013 1000010000020@unknown@formal@none@1@S@The ⌊∗Extensible Markup Language∗⌋ (⌊∗XML∗⌋) is a general-purpose ⌊/specification/⌋ for creating custom ⌊>markup language>⌋s.@@@@1@14@@oe@26-8-2013 1000010000030@unknown@formal@none@1@S@It is classified as an ⌊>extensible language>⌋ because it allows its users to define their own elements.@@@@1@17@@oe@26-8-2013 1000010000040@unknown@formal@none@1@S@Its primary purpose is to facilitate the sharing of structured data across different information systems, particularly via the ⌊>Internet>⌋, and it is used both to encode documents and to ⌊>serialize>⌋ data.@@@@1@31@@oe@26-8-2013 1000010000050@unknown@formal@none@1@S@In the latter context, it is comparable with other text-based serialization languages such as ⌊>JSON>⌋ and ⌊>YAML>⌋.@@@@1@17@@oe@26-8-2013 1000010000060@unknown@formal@none@1@S@It started as a simplified subset of the ⌊>Standard Generalized Markup Language>⌋ (SGML), and is designed to be relatively human-legible.@@@@1@20@@oe@26-8-2013 1000010000070@unknown@formal@none@1@S@By adding ⌊>semantic>⌋ constraints, application languages can be implemented in XML.@@@@1@11@@oe@26-8-2013 1000010000080@unknown@formal@none@1@S@These include ⌊>XHTML>⌋, ⌊>RSS>⌋, ⌊>MathML>⌋, ⌊>GraphML>⌋, ⌊>Scalable Vector Graphics>⌋, ⌊>MusicXML>⌋, and thousands of others.@@@@1@14@@oe@26-8-2013 1000010000090@unknown@formal@none@1@S@Moreover, XML is sometimes used as the ⌊>specification language>⌋ for such application languages.@@@@1@13@@oe@26-8-2013 1000010000100@unknown@formal@none@1@S@XML is ⌊>recommended>⌋ by the ⌊>World Wide Web Consortium>⌋ (W3C).@@@@1@10@@oe@26-8-2013 1000010000110@unknown@formal@none@1@S@It is a fee-free ⌊>open standard>⌋.@@@@1@6@@oe@26-8-2013 1000010000120@unknown@formal@none@1@S@The recommendation specifies both the ⌊>lexical grammar>⌋ and the requirements for ⌊>parsing>⌋.@@@@1@12@@oe@26-8-2013 1000010000130@unknown@formal@none@1@S@⌊=Well-formed and valid XML documents¦2=⌋@@@@1@5@@oe@26-8-2013 1000010000140@unknown@formal@none@1@S@There are two levels of correctness of an XML document:@@@@1@10@@oe@26-8-2013 1000010000150@unknown@formal@none@1@S@⌊•⌊#⌊∗Well-formed∗⌋.@@@@1@1@@oe@26-8-2013 1000010000160@unknown@formal@none@1@S@A well-formed document conforms to all of XML's syntax rules.@@@@1@10@@oe@26-8-2013 1000010000170@unknown@formal@none@1@S@For example, if a start-tag appears without a corresponding end-tag, it is not ⌊/well-formed/⌋.@@@@1@14@@oe@26-8-2013 1000010000180@unknown@formal@none@1@S@A document that is not well-formed is not considered to be XML; a ⌊/conforming parser/⌋ is not allowed to process it.#⌋@@@@1@21@@oe@26-8-2013 1000010000190@unknown@formal@none@1@S@⌊#⌊∗Valid∗⌋.@@@@1@1@@oe@26-8-2013 1000010000200@unknown@formal@none@1@S@A valid document additionally conforms to some semantic rules.@@@@1@9@@oe@26-8-2013 1000010000210@unknown@formal@none@1@S@These rules are either user-defined, or included as an ⌊>XML schema>⌋ or ⌊>DTD>⌋.@@@@1@13@@oe@26-8-2013 1000010000220@unknown@formal@none@1@S@For example, if a document contains an undefined element, then it is not ⌊/valid/⌋; a ⌊/validating parser/⌋ is not allowed to process it.#⌋•⌋@@@@1@23@@oe@26-8-2013 1000010000230@unknown@formal@none@1@S@⌊=Well-formed documents: XML syntax¦2=⌋@@@@1@4@@oe@26-8-2013 1000010000240@unknown@formal@none@1@S@As long as only ⌊>well-formedness>⌋ is required, XML is a generic framework for storing any amount of text or any data whose structure can be represented as a ⌊>tree>⌋.@@@@1@29@@oe@26-8-2013 1000010000250@unknown@formal@none@1@S@The only indispensable syntactical requirement is that the document has exactly one ⌊∗root element∗⌋ (alternatively called the ⌊∗document element∗⌋).@@@@1@19@@oe@26-8-2013 1000010000260@unknown@formal@none@1@S@This means that the text must be enclosed between a root start-tag and a corresponding end-tag.@@@@1@16@@oe@26-8-2013 1000010000270@unknown@formal@none@1@S@The following is a "well-formed" XML document:@@@@1@7@@oe@26-8-2013 1000010000280@unknown@formal@none@1@S@The root element can be preceded by an optional ⌊∗XML declaration∗⌋.@@@@1@11@@oe@26-8-2013 1000010000290@unknown@formal@none@1@S@This element states what version of XML is in use (normally 1.0); it may also contain information about ⌊>character encoding>⌋ and external dependencies.@@@@1@23@@oe@26-8-2013 1000010000300@unknown@formal@none@1@S@The specification ⌊/requires/⌋ that ⌊>processors>⌋ of XML support the pan-⌊>Unicode>⌋ ⌊>character encoding>⌋s ⌊>UTF-8>⌋ and ⌊>UTF-16>⌋ (⌊>UTF-32>⌋ is not mandatory).@@@@1@19@@oe@26-8-2013 1000010000310@unknown@formal@none@1@S@The use of more limited encodings, such as those based on ⌊>ISO/IEC 8859>⌋, is acknowledged and is widely used and supported.@@@@1@21@@oe@26-8-2013 1000010000320@unknown@formal@none@1@S@⌊∗Comments∗⌋ can be placed anywhere in the tree, including in the text if the content of the element is text or #PCDATA.@@@@1@22@@oe@26-8-2013 1000010000330@unknown@formal@none@1@S@XML comments start with ⌊∗<!--∗⌋ and end with ⌊∗-->∗⌋.@@@@1@9@@oe@26-8-2013 1000010000340@unknown@formal@none@1@S@Two dashes (--) may not appear anywhere in the text of the comment.@@@@1@13@@oe@26-8-2013 1000010000350@unknown@formal@none@1@S@In any meaningful application, additional markup is used to structure the contents of the XML document.@@@@1@16@@oe@26-8-2013 1000010000360@unknown@formal@none@1@S@The text enclosed by the root tags may contain an arbitrary number of XML elements.@@@@1@15@@oe@26-8-2013 1000010000370@unknown@formal@none@1@S@The basic syntax for one ⌊∗element∗⌋ is: The two instances of »name« are referred to as the ⌊∗start-tag∗⌋ and ⌊∗end-tag∗⌋, respectively.@@@@1@21@@oe@26-8-2013 1000010000380@unknown@formal@none@1@S@Here, »content« is some text which may again contain XML elements.@@@@1@11@@oe@26-8-2013 1000010000390@unknown@formal@none@1@S@So, a generic XML document contains a ⌊>tree-based data structure>⌋.@@@@1@10@@oe@26-8-2013 1000010000400@unknown@formal@none@1@S@Here is an example of a structured XML document:@@@@1@9@@oe@26-8-2013 1000010000410@unknown@formal@none@1@S@Attribute values must always be quoted, using single or double quotes; and each attribute name must appear only once in any element.@@@@1@22@@oe@26-8-2013 1000010000420@unknown@formal@none@1@S@XML requires that elements be properly nested — elements may never overlap, and so must be closed in the opposite order to which they are opened.@@@@1@26@@oe@26-8-2013 1000010000430@unknown@formal@none@1@S@For example, this fragment of code below cannot be part of a well-formed XML document because the ⌊/title/⌋ and ⌊/author/⌋ elements are closed in the wrong order: One way of writing the same information in a way which could be incorporated into a well-formed XML document is as follows:@@@@1@49@@oe@26-8-2013 1000010000440@unknown@formal@none@1@S@XML provides special syntax for representing an element with empty content.@@@@1@11@@oe@26-8-2013 1000010000450@unknown@formal@none@1@S@Instead of writing a start-tag followed immediately by an end-tag, a document may contain an empty-element tag.@@@@1@17@@oe@26-8-2013 1000010000460@unknown@formal@none@1@S@An empty-element tag resembles a start-tag but contains a slash just before the closing angle bracket.@@@@1@16@@oe@26-8-2013 1000010000470@unknown@formal@none@1@S@The following three examples are equivalent in XML: An empty-element may contain attributes:@@@@1@13@@oe@26-8-2013 1000010000480@unknown@formal@none@1@S@⌊=Entity references¦3=⌋@@@@1@2@@oe@26-8-2013 1000010000490@unknown@formal@none@1@S@An ⌊>entity>⌋ in XML is a named body of data, usually text.@@@@1@12@@oe@26-8-2013 1000010000500@unknown@formal@none@1@S@Entities are often used to represent single characters that cannot easily be entered on the keyboard; they are also used to represent pieces of standard ("boilerplate") text that occur in many documents, especially if there is a need to allow such text to be changed in one place only.@@@@1@49@@oe@26-8-2013 1000010000510@unknown@formal@none@1@S@Special characters can be represented either using ⌊>entity>⌋ references, or by means of ⌊>numeric character reference>⌋s.@@@@1@16@@oe@26-8-2013 1000010000520@unknown@formal@none@1@S@An example of a numeric character reference is "⌊◊€◊⌋", which refers to the ⌊>Euro symbol>⌋ by means of its ⌊>Unicode>⌋ codepoint in ⌊>hexadecimal>⌋.@@@@1@23@@oe@26-8-2013 1000010000530@unknown@formal@none@1@S@An entity reference is a ⌊>placeholder>⌋ that represents that entity.@@@@1@10@@oe@26-8-2013 1000010000540@unknown@formal@none@1@S@It consists of the entity's name preceded by an ⌊>ampersand>⌋ ("⌊◊&◊⌋") and followed by a ⌊>semicolon>⌋ ("⌊◊;◊⌋").@@@@1@17@@oe@26-8-2013 1000010000550@unknown@formal@none@1@S@XML has five ⌊>predeclared>⌋ entities:@@@@1@5@@oe@26-8-2013 1000010000560@unknown@formal@none@1@S@⌊•⌊#⌊◊&◊⌋ (& or "ampersand")#⌋@@@@1@4@@oe@26-8-2013 1000010000570@unknown@formal@none@1@S@⌊#⌊◊<◊⌋ (< or "less than")#⌋@@@@1@5@@oe@26-8-2013 1000010000580@unknown@formal@none@1@S@⌊#⌊◊>◊⌋ (> or "greater than")#⌋@@@@1@5@@oe@26-8-2013 1000010000590@unknown@formal@none@1@S@⌊#⌊◊'◊⌋ (' or "apostrophe")#⌋@@@@1@4@@oe@26-8-2013 1000010000600@unknown@formal@none@1@S@⌊#⌊◊"◊⌋ (" or "quotation mark")#⌋•⌋@@@@1@5@@oe@26-8-2013 1000010000610@unknown@formal@none@1@S@Here is an example using a predeclared XML entity to represent the ampersand in the name "AT&T": Additional entities (beyond the predefined ones) can be declared in the document's ⌊>Document Type Definition (DTD)>⌋.@@@@1@33@@oe@26-8-2013 1000010000620@unknown@formal@none@1@S@A basic example of doing so in a minimal internal DTD follows.@@@@1@12@@oe@26-8-2013 1000010000630@unknown@formal@none@1@S@Declared entities can describe single characters or pieces of text, and can reference each other.@@@@1@15@@oe@26-8-2013 1000010000640@unknown@formal@none@1@S@When viewed in a suitable browser, the XML document above appears as:@@@@1@12@@oe@26-8-2013 1000010000650@unknown@formal@none@1@S@Copyright © 2006, XYZ Enterprises@@@@1@5@@oe@26-8-2013 1000010000660@unknown@formal@none@1@S@⌊=Numeric character references¦4=⌋@@@@1@3@@oe@26-8-2013 1000010000670@unknown@formal@none@1@S@Numeric character references look like entity references, but instead of a name, they contain the "⌊◊⌊>#>⌋◊⌋" character followed by a number.@@@@1@21@@oe@26-8-2013 1000010000680@unknown@formal@none@1@S@The number (in decimal or "⌊◊x◊⌋"-prefixed ⌊>hexadecimal>⌋) represents a Unicode code point.@@@@1@12@@oe@26-8-2013 1000010000690@unknown@formal@none@1@S@Unlike entity references, they are neither predeclared nor do they need to be declared in the document's DTD.@@@@1@18@@oe@26-8-2013 1000010000700@unknown@formal@none@1@S@They have typically been used to represent characters that are not easily encodable, such as an ⌊>Arabic>⌋ character in a document produced on a European computer.@@@@1@26@@oe@26-8-2013 1000010000710@unknown@formal@none@1@S@The ampersand in the "AT&T" example could also be ⌊>escaped>⌋ like this (decimal 38 and hexadecimal 26 both represent the Unicode code point for the "&" character):@@@@1@27@@oe@26-8-2013 1000010000720@unknown@formal@none@1@S@Similarly, in the previous example, notice that “©” is used to generate the “©” symbol.@@@@1@15@@oe@26-8-2013 1000010000730@unknown@formal@none@1@S@See also ⌊>numeric character reference>⌋s.@@@@1@5@@oe@26-8-2013 1000010000740@unknown@formal@none@1@S@⌊=Well-formed documents¦3=⌋@@@@1@2@@oe@26-8-2013 1000010000750@unknown@formal@none@1@S@In XML, a ⌊>well-formed>⌋ document must conform to the following rules, among others:@@@@1@13@@oe@26-8-2013 1000010000760@unknown@formal@none@1@S@⌊•⌊#Non-empty elements are ⌊>delimited>⌋ by both a start-tag and an end-tag.#⌋@@@@1@11@@oe@26-8-2013 1000010000770@unknown@formal@none@1@S@⌊#Empty elements may be marked with an empty-element (self-closing) tag, such as ⌊◊<IAmEmpty />◊⌋.@@@@1@14@@oe@26-8-2013 1000010000780@unknown@formal@none@1@S@This is equal to ⌊◊<IAmEmpty></IAmEmpty>◊⌋.#⌋@@@@1@5@@oe@26-8-2013 1000010000790@unknown@formal@none@1@S@⌊#All attribute values are quoted with either single (') or double (") quotes.@@@@1@13@@oe@26-8-2013 1000010000800@unknown@formal@none@1@S@Single quotes close a single quote and double quotes close a double quote.#⌋@@@@1@13@@oe@26-8-2013 1000010000810@unknown@formal@none@1@S@⌊#Tags may be nested but must not overlap.@@@@1@8@@oe@26-8-2013 1000010000820@unknown@formal@none@1@S@Each non-root element must be completely contained in another element.#⌋@@@@1@10@@oe@26-8-2013 1000010000830@unknown@formal@none@1@S@⌊#The document complies with its declared character encoding.@@@@1@8@@oe@26-8-2013 1000010000840@unknown@formal@none@1@S@The encoding may be declared or implied externally, such as in "Content-Type" headers when a document is transported via ⌊>HTTP>⌋, or internally, using explicit markup at the very beginning of the document.@@@@1@32@@oe@26-8-2013 1000010000850@unknown@formal@none@1@S@When no such declaration exists, a Unicode encoding is assumed, as defined by a Unicode ⌊>Byte Order Mark>⌋ before the document's first character.@@@@1@23@@oe@26-8-2013 1000010000860@unknown@formal@none@1@S@If the mark does not exist, UTF-8 encoding is assumed.#⌋•⌋@@@@1@10@@oe@26-8-2013 1000010000870@unknown@formal@none@1@S@Element names are case-sensitive.@@@@1@4@@oe@26-8-2013 1000010000880@unknown@formal@none@1@S@For example, the following is a well-formed matching pair:@@@@1@9@@oe@26-8-2013 1000010000890@unknown@formal@none@1@S@⌊⇥⌊◊<Step>◊⌋ ... ⌊◊</Step>◊⌋⇥⌋@@@@1@3@@oe@26-8-2013 1000010000900@unknown@formal@none@1@S@whereas this is not@@@@1@4@@oe@26-8-2013 1000010000910@unknown@formal@none@1@S@⌊⇥⌊◊<Step>◊⌋ ... ⌊◊</step>◊⌋⇥⌋@@@@1@3@@oe@26-8-2013 1000010000920@unknown@formal@none@1@S@By carefully choosing the names of the XML elements one may convey the meaning of the data in the ⌊>markup>⌋.@@@@1@20@@oe@26-8-2013 1000010000930@unknown@formal@none@1@S@This increases human readability while retaining the rigor needed for software parsing.@@@@1@12@@oe@26-8-2013 1000010000940@unknown@formal@none@1@S@Choosing meaningful names implies the ⌊>semantics>⌋ of elements and attributes to a human reader without reference to external documentation.@@@@1@19@@oe@26-8-2013 1000010000950@unknown@formal@none@1@S@However, this can lead to verbosity, which complicates ⌊>authoring>⌋ and increases ⌊>file size>⌋.@@@@1@13@@oe@26-8-2013 1000010000960@unknown@formal@none@1@S@⌊=Automatic verification¦3=⌋@@@@1@2@@oe@26-8-2013 1000010000970@unknown@formal@none@1@S@It is relatively simple to verify that a document is well-formed or validated XML, because the rules of well-formedness and validation of XML are designed for portability of tools.@@@@1@29@@oe@26-8-2013 1000010000980@unknown@formal@none@1@S@The idea is that any tool designed to work with XML files will be able to work with XML files written in any XML language (or XML application).@@@@1@28@@oe@26-8-2013 1000010000990@unknown@formal@none@1@S@Here are some examples of ways to verify XML documents:@@@@1@10@@oe@26-8-2013 1000010001000@unknown@formal@none@1@S@⌊•⌊#load it into an XML-capable browser, such as ⌊>Firefox>⌋ or ⌊>Internet Explorer>⌋#⌋@@@@1@12@@oe@26-8-2013 1000010001010@unknown@formal@none@1@S@⌊#use a tool like xmlwf (usually bundled with ⌊>expat>⌋)#⌋@@@@1@9@@oe@26-8-2013 1000010001020@unknown@formal@none@1@S@⌊#parse the document, for instance in ⌊>Ruby>⌋:#⌋•⌋@@@@1@7@@oe@26-8-2013 1000010001030@unknown@formal@none@1@S@⌊πirb> require "rexml/document" irb> include REXML irb> doc = Document.new(File.new("test.xml")).rootπ⌋@@@@1@10@@oe@26-8-2013 1000010001040@unknown@formal@none@1@S@⌊=Valid documents: XML semantics¦2=⌋@@@@1@4@@oe@26-8-2013 1000010001050@unknown@formal@none@1@S@By leaving the names, allowable hierarchy, and meanings of the elements and attributes open and definable by a customizable ⌊/⌊>schema>⌋ or ⌊>DTD>⌋/⌋, XML provides a syntactic foundation for the creation of purpose-specific, XML-based markup languages.@@@@1@35@@oe@26-8-2013 1000010001060@unknown@formal@none@1@S@The general syntax of such languages is rigid — documents must adhere to the general rules of XML, ensuring that all XML-aware software can at least read and understand the relative arrangement of information within them.@@@@1@36@@oe@26-8-2013 1000010001070@unknown@formal@none@1@S@The schema merely supplements the syntax rules with a set of constraints.@@@@1@12@@oe@26-8-2013 1000010001080@unknown@formal@none@1@S@Schemas typically restrict element and attribute names and their allowable containment hierarchies, such as only allowing an element named 'birthday' to contain one element named 'month' and one element named 'day', each of which has to contain only character data.@@@@1@40@@oe@26-8-2013 1000010001090@unknown@formal@none@1@S@The constraints in a schema may also include ⌊>data type>⌋ assignments that affect how information is processed; for example, the 'month' element's character data may be defined as being a month according to a particular schema language's conventions, perhaps meaning that it must not only be formatted a certain way, but also must not be processed as if it were some other type of data.@@@@1@65@@oe@26-8-2013 1000010001100@unknown@formal@none@1@S@An XML document that complies with a particular schema/DTD, in addition to being well-formed, is said to be ⌊∗valid∗⌋.@@@@1@19@@oe@26-8-2013 1000010001110@unknown@formal@none@1@S@An XML schema is a description of a type of XML document, typically expressed in terms of ⌊>constraints>⌋ on the structure and content of documents of that type, above and beyond the basic constraints imposed by XML itself.@@@@1@38@@oe@26-8-2013 1000010001120@unknown@formal@none@1@S@A number of standard and proprietary XML schema languages have emerged for the purpose of formally expressing such schemas, and some of these languages are XML-based, themselves.@@@@1@27@@oe@26-8-2013 1000010001130@unknown@formal@none@1@S@Before the advent of generalised data description languages such as SGML and XML, software designers had to define special ⌊>file format>⌋s or small languages to share data between programs.@@@@1@29@@oe@26-8-2013 1000010001140@unknown@formal@none@1@S@This required writing detailed ⌊>specifications>⌋ and special-purpose parsers and ⌊>writer>⌋s.@@@@1@10@@oe@26-8-2013 1000010001150@unknown@formal@none@1@S@XML's regular structure and strict parsing rules allow software designers to leave parsing to standard tools, and since XML provides a general, ⌊>data model>⌋-oriented framework for the development of application-specific languages, software designers need only concentrate on the development of rules for their data, at relatively high levels of abstraction.@@@@1@50@@oe@26-8-2013 1000010001160@unknown@formal@none@1@S@Well-tested tools exist to ⌊>validate>⌋ an XML document "against" a schema: the tool automatically ⌊>verifies>⌋ whether the document conforms to constraints expressed in the schema.@@@@1@25@@oe@26-8-2013 1000010001170@unknown@formal@none@1@S@Some of these validation tools are included in XML parsers, and some are packaged separately.@@@@1@15@@oe@26-8-2013 1000010001180@unknown@formal@none@1@S@Other usages of schemas exist: XML editors, for instance, can use schemas to support the editing process (by suggesting valid elements and attributes names, etc).@@@@1@25@@oe@26-8-2013 1000010001190@unknown@formal@none@1@S@⌊=DTD¦4=⌋@@@@1@1@@oe@26-8-2013 1000010001200@unknown@formal@none@1@S@The oldest schema format for XML is the ⌊>Document Type Definition>⌋ (DTD), inherited from SGML.@@@@1@15@@oe@26-8-2013 1000010001210@unknown@formal@none@1@S@While DTD support is ubiquitous due to its inclusion in the XML 1.0 standard, it is seen as limited for the following reasons:@@@@1@23@@oe@26-8-2013 1000010001220@unknown@formal@none@1@S@⌊•⌊#It has no support for newer ⌊>feature>⌋s of XML, most importantly ⌊>namespaces>⌋.#⌋@@@@1@12@@oe@26-8-2013 1000010001230@unknown@formal@none@1@S@⌊#It lacks expressiveness.@@@@1@3@@oe@26-8-2013 1000010001240@unknown@formal@none@1@S@Certain formal aspects of an XML document cannot be captured in a DTD.#⌋@@@@1@13@@oe@26-8-2013 1000010001250@unknown@formal@none@1@S@⌊#It uses a custom non-XML syntax, inherited from ⌊>SGML>⌋, to describe the schema.#⌋•⌋@@@@1@13@@oe@26-8-2013 1000010001260@unknown@formal@none@1@S@DTD is still used in many applications because it is considered the easiest to read and write.@@@@1@17@@oe@26-8-2013 1000010001270@unknown@formal@none@1@S@⌊=XML Schema¦4=⌋@@@@1@2@@oe@26-8-2013 1000010001280@unknown@formal@none@1@S@A newer ⌊>XML schema>⌋ language, described by the W3C as the successor of DTDs, is ⌊>XML Schema>⌋, or more informally referred to by the ⌊>initialism>⌋ for XML Schema instances, XSD (XML Schema Definition).@@@@1@33@@oe@26-8-2013 1000010001290@unknown@formal@none@1@S@XSDs are far more powerful than DTDs in describing XML languages.@@@@1@11@@oe@26-8-2013 1000010001300@unknown@formal@none@1@S@They use a rich ⌊>datatyping>⌋ system, allow for more detailed constraints on an XML document's logical structure, and must be processed in a more robust validation framework.@@@@1@27@@oe@26-8-2013 1000010001310@unknown@formal@none@1@S@XSDs also use an XML-based format, which makes it possible to use ordinary XML tools to help process them, although XSD implementations require much more than just the ability to read XML.@@@@1@32@@oe@26-8-2013 1000010001320@unknown@formal@none@1@S@Criticisms of XSD include the following:@@@@1@6@@oe@26-8-2013 1000010001330@unknown@formal@none@1@S@⌊•⌊#The specification is very large, which makes it difficult to understand and implement.#⌋@@@@1@13@@oe@26-8-2013 1000010001340@unknown@formal@none@1@S@⌊#The XML-based syntax leads to verbosity in schema descriptions, which makes XSDs harder to read and write.#⌋@@@@1@17@@oe@26-8-2013 1000010001350@unknown@formal@none@1@S@⌊#Schema validation can be an expensive addition to XML parsing, especially for high volume systems.#⌋@@@@1@15@@oe@26-8-2013 1000010001360@unknown@formal@none@1@S@⌊#The modeling capabilities are very limited, with no ability to allow attributes to influence ⌊>content model>⌋s.#⌋@@@@1@16@@oe@26-8-2013 1000010001370@unknown@formal@none@1@S@⌊#The ⌊>type derivation model>⌋ is very limited, in particular that derivation by extension is rarely useful.#⌋@@@@1@16@@oe@26-8-2013 1000010001380@unknown@formal@none@1@S@⌊#Database-related ⌊>data transfer>⌋ is supported with ideas such as ⌊>nillability>⌋, but the requirements of industrial publishing are under-supported.#⌋@@@@1@18@@oe@26-8-2013 1000010001390@unknown@formal@none@1@S@⌊#The key/⌊>keyref>⌋/⌊>uniqueness>⌋ mechanisms are not type-aware.#⌋@@@@1@6@@oe@26-8-2013 1000010001400@unknown@formal@none@1@S@⌊#The ⌊>PSVI>⌋ concept (Post Schema Validation Infoset) does not have a standard XML representation or ⌊>Application Programming Interface>⌋, thus it works against ⌊>vendor independence>⌋ unless revalidation is performed.#⌋•⌋@@@@1@28@@oe@26-8-2013 1000010001410@unknown@formal@none@1@S@⌊=RELAX NG¦4=⌋@@@@1@2@@oe@26-8-2013 1000010001420@unknown@formal@none@1@S@Another popular schema language for XML is ⌊>RELAX NG>⌋.@@@@1@9@@oe@26-8-2013 1000010001430@unknown@formal@none@1@S@Initially specified by ⌊>OASIS>⌋, RELAX NG is now also an ISO international standard (as part of ⌊>DSDL>⌋).@@@@1@17@@oe@26-8-2013 1000010001440@unknown@formal@none@1@S@It has two formats: an XML based syntax and a non-XML compact syntax.@@@@1@13@@oe@26-8-2013 1000010001450@unknown@formal@none@1@S@The compact syntax aims to increase readability and writability but, since there is a well-defined way to translate the compact syntax to the XML syntax and back again by means of ⌊>James Clark>⌋'s ⌊> Trang conversion tool>⌋, the advantage of using standard XML tools is not lost.@@@@1@47@@oe@26-8-2013 1000010001460@unknown@formal@none@1@S@RELAX NG has a simpler definition and validation framework than XML Schema, making it easier to use and implement.@@@@1@19@@oe@26-8-2013 1000010001470@unknown@formal@none@1@S@It also has the ability to use ⌊>datatype>⌋ framework ⌊>plug-in>⌋s; a RELAX NG schema author, for example, can require values in an XML document to conform to definitions in XML Schema Datatypes.@@@@1@32@@oe@26-8-2013 1000010001480@unknown@formal@none@1@S@⌊=ISO DSDL and other schema languages¦4=⌋@@@@1@6@@oe@26-8-2013 1000010001490@unknown@formal@none@1@S@The ISO ⌊>DSDL>⌋ (Document Schema Description Languages) standard brings together a comprehensive set of small schema languages, each targeted at specific problems.@@@@1@22@@oe@26-8-2013 1000010001500@unknown@formal@none@1@S@DSDL includes ⌊>RELAX NG>⌋ full and compact syntax, ⌊>Schematron>⌋ assertion language, and languages for defining datatypes, character repertoire constraints, renaming and entity expansion, and namespace-based ⌊>routing>⌋ of document fragments to different validators.@@@@1@32@@oe@26-8-2013 1000010001510@unknown@formal@none@1@S@DSDL schema languages do not have the vendor support of XML Schemas yet, and are to some extent a grassroots reaction of industrial publishers to the lack of utility of XML Schemas for ⌊>publishing>⌋.@@@@1@34@@oe@26-8-2013 1000010001520@unknown@formal@none@1@S@Some schema languages not only describe the structure of a particular XML format but also offer limited facilities to influence processing of individual XML files that conform to this format.@@@@1@30@@oe@26-8-2013 1000010001530@unknown@formal@none@1@S@DTDs and XSDs both have this ability; they can for instance provide attribute defaults.@@@@1@14@@oe@26-8-2013 1000010001540@unknown@formal@none@1@S@RELAX NG and Schematron intentionally do not provide these; for example the ⌊>infoset>⌋ augmentation facility.@@@@1@15@@oe@26-8-2013 1000010001550@unknown@formal@none@1@S@⌊=International use¦3=⌋@@@@1@2@@oe@26-8-2013 1000010001560@unknown@formal@none@1@S@XML supports the direct use of almost any Unicode character in element names, attributes, comments, character data, and processing instructions (other than the ones that have special symbolic meaning in XML itself, such as the open corner bracket, "<").@@@@1@39@@oe@26-8-2013 1000010001570@unknown@formal@none@1@S@Therefore, the following is a well-formed XML document, even though it includes both ⌊>Chinese>⌋ and ⌊>Cyrillic>⌋ characters:@@@@1@17@@oe@26-8-2013 1000010001580@unknown@formal@none@1@S@⌊=Displaying XML on the web¦2=⌋@@@@1@5@@oe@26-8-2013 1000010001590@unknown@formal@none@1@S@XML documents do not carry information about how to display the data.@@@@1@12@@oe@26-8-2013 1000010001600@unknown@formal@none@1@S@Without using ⌊>CSS>⌋ or ⌊>XSL>⌋, a generic XML document is rendered as raw XML text by most ⌊>web browser>⌋s.@@@@1@19@@oe@26-8-2013 1000010001610@unknown@formal@none@1@S@Some display it with 'handles' (e.g. + and - signs in the margin) that allow parts of the structure to be expanded or collapsed with mouse-clicks.@@@@1@26@@oe@26-8-2013 1000010001620@unknown@formal@none@1@S@In order to style the rendering in a browser with CSS, the XML document must include a reference to the ⌊>stylesheet>⌋:@@@@1@21@@oe@26-8-2013 1000010001630@unknown@formal@none@1@S@Note that this is different from specifying such a stylesheet in HTML, which uses the ⌊◊<link>◊⌋ element.@@@@1@17@@oe@26-8-2013 1000010001640@unknown@formal@none@1@S@⌊>Extensible Stylesheet Language>⌋ (XSL) can be used to alter the format of XML data, either into HTML or other formats that are suitable for a browser to display.@@@@1@28@@oe@26-8-2013 1000010001650@unknown@formal@none@1@S@To specify ⌊>client-side>⌋ ⌊>XSL Transformation>⌋ (XSLT), the following processing instruction is required in the XML:@@@@1@15@@oe@26-8-2013 1000010001660@unknown@formal@none@1@S@Client-side XSLT is supported by many ⌊>web browser>⌋s.@@@@1@8@@oe@26-8-2013 1000010001670@unknown@formal@none@1@S@Alternatively, one may use XSL to convert XML into a displayable format ⌊/on the ⌊>server>⌋/⌋ rather than being dependent on the ⌊>end-user>⌋'s browser capabilities.@@@@1@24@@oe@26-8-2013 1000010001680@unknown@formal@none@1@S@The end-user is not aware of what has gone on 'behind the scenes'; all they see is well-formatted, displayable data.@@@@1@20@@oe@26-8-2013 1000010001690@unknown@formal@none@1@S@See the XSLT article for ⌊>an example of server-side XSLT in action>⌋.@@@@1@12@@oe@26-8-2013 1000010001700@unknown@formal@none@1@S@⌊=XML extensions¦2=⌋@@@@1@2@@oe@26-8-2013 1000010001710@unknown@formal@none@1@S@⌊•⌊#⌊∗⌊>XPath>⌋∗⌋ makes it possible to refer to individual parts of an XML document.@@@@1@13@@oe@26-8-2013 1000010001720@unknown@formal@none@1@S@This provides random access to XML data for other technologies, including XSLT, XSL-FO, XQuery etc.@@@@1@15@@oe@26-8-2013 1000010001730@unknown@formal@none@1@S@XPath expressions can refer to all or part of the text, data and values in XML elements, attributes, processing instructions, comments etc.@@@@1@22@@oe@26-8-2013 1000010001740@unknown@formal@none@1@S@They can also access the names of elements and attributes.@@@@1@10@@oe@26-8-2013 1000010001750@unknown@formal@none@1@S@XPaths can be used in both valid and well-formed XML, with and without defined namespaces.#⌋@@@@1@15@@oe@26-8-2013 1000010001760@unknown@formal@none@1@S@⌊#⌊∗⌊>XInclude>⌋∗⌋ defines the ability for XML files to include all or part of an external file.@@@@1@16@@oe@26-8-2013 1000010001770@unknown@formal@none@1@S@When processing is complete, the final XML infoset has no XInclude elements, but instead has copied the documents or parts thereof into the final infoset.@@@@1@25@@oe@26-8-2013 1000010001780@unknown@formal@none@1@S@It uses XPath to refer to a portion of the document for partial inclusions.#⌋@@@@1@14@@oe@26-8-2013 1000010001790@unknown@formal@none@1@S@⌊#⌊∗⌊>XQuery>⌋∗⌋ is to XML and ⌊>XML Databases>⌋ what ⌊>SQL>⌋ and ⌊>PL/SQL>⌋ are to ⌊>relational databases>⌋: ways to access, manipulate and return XML.#⌋@@@@1@22@@oe@26-8-2013 1000010001800@unknown@formal@none@1@S@⌊#⌊∗⌊>XML Namespace>⌋s∗⌋ enable the same document to contain XML elements and attributes taken from different vocabularies, without any ⌊>naming collision>⌋s occurring.#⌋@@@@1@21@@oe@26-8-2013 1000010001810@unknown@formal@none@1@S@⌊#⌊∗⌊>XML Signature>⌋∗⌋ defines the syntax and processing rules for creating ⌊>digital signatures>⌋ on XML content.#⌋@@@@1@15@@oe@26-8-2013 1000010001820@unknown@formal@none@1@S@⌊#⌊∗⌊>XML Encryption>⌋∗⌋ defines the syntax and processing rules for ⌊>encrypting>⌋ XML content.#⌋@@@@1@12@@oe@26-8-2013 1000010001830@unknown@formal@none@1@S@⌊#⌊∗⌊>XPointer>⌋∗⌋ is a system for addressing components of XML-based internet media.#⌋•⌋@@@@1@11@@oe@26-8-2013 1000010001840@unknown@formal@none@1@S@XML files may be served with a variety of ⌊>Media types>⌋.@@@@1@11@@oe@26-8-2013 1000010001850@unknown@formal@none@1@S@RFC 3023 defines the types "application/xml" and "text/xml", which say only that the data is in XML, and nothing about its semantics.@@@@1@22@@oe@26-8-2013 1000010001860@unknown@formal@none@1@S@The use of "text/xml" has been criticized as a potential source of encoding problems but is now in the process of being deprecated.@@@@1@23@@oe@26-8-2013 1000010001870@unknown@formal@none@1@S@RFC 3023 also recommends that XML-based languages be given media types beginning in "application/" and ending in "+xml"; for example "application/atom+xml" for ⌊>Atom>⌋.@@@@1@23@@oe@26-8-2013 1000010001880@unknown@formal@none@1@S@This page discusses further ⌊>XML and MIME>⌋.@@@@1@7@@oe@26-8-2013 1000010001890@unknown@formal@none@1@S@⌊=Processing XML files¦2=⌋@@@@1@3@@oe@26-8-2013 1000010001900@unknown@formal@none@1@S@Three traditional techniques for processing XML files are:@@@@1@8@@oe@26-8-2013 1000010001910@unknown@formal@none@1@S@⌊•⌊#Using a programming language and the ⌊>SAX>⌋ ⌊>API>⌋.#⌋@@@@1@8@@oe@26-8-2013 1000010001920@unknown@formal@none@1@S@⌊#Using a programming language and the ⌊>DOM>⌋ ⌊>API>⌋.#⌋@@@@1@8@@oe@26-8-2013 1000010001930@unknown@formal@none@1@S@⌊#Using a transformation engine and a filter#⌋•⌋@@@@1@7@@oe@26-8-2013 1000010001940@unknown@formal@none@1@S@More recent and emerging techniques for processing XML files are:@@@@1@10@@oe@26-8-2013 1000010001950@unknown@formal@none@1@S@⌊•⌊#Pull Parsing#⌋@@@@1@2@@oe@26-8-2013 1000010001960@unknown@formal@none@1@S@⌊#Non-Extractive Parsing (i.e. in-situ parsing)#⌋@@@@1@5@@oe@26-8-2013 1000010001970@unknown@formal@none@1@S@⌊#Data binding#⌋•⌋@@@@1@2@@oe@26-8-2013 1000010001980@unknown@formal@none@1@S@⌊=Simple API for XML (SAX)¦3=⌋@@@@1@5@@oe@26-8-2013 1000010001990@unknown@formal@none@1@S@⌊>SAX>⌋ is a ⌊>lexical>⌋, ⌊>event-driven>⌋ interface in which a document is read serially and its contents are reported as "⌊>callback>⌋s" to various ⌊>method>⌋s on a ⌊>handler object>⌋ of the user's design.@@@@1@31@@oe@26-8-2013 1000010002000@unknown@formal@none@1@S@SAX is fast and efficient to implement, but difficult to use for extracting information at random from the XML, since it tends to burden the application author with keeping track of what part of the document is being processed.@@@@1@39@@oe@26-8-2013 1000010002010@unknown@formal@none@1@S@It is better suited to situations in which certain types of information are always handled the same way, no matter where they occur in the document.@@@@1@26@@oe@26-8-2013 1000010002020@unknown@formal@none@1@S@⌊=DOM¦3=⌋@@@@1@1@@oe@26-8-2013 1000010002030@unknown@formal@none@1@S@⌊>DOM>⌋ is an ⌊>interface>⌋-oriented ⌊>Application Programming Interface>⌋ that allows for navigation of the entire document as if it were a tree of "⌊>Node>⌋" ⌊>object>⌋s representing the document's contents.@@@@1@28@@oe@26-8-2013 1000010002040@unknown@formal@none@1@S@A DOM document can be created by a parser, or can be generated manually by users (with limitations).@@@@1@18@@oe@26-8-2013 1000010002050@unknown@formal@none@1@S@Data types in DOM Nodes are abstract; implementations provide their own ⌊>programming>⌋ language-specific ⌊>binding>⌋s.@@@@1@14@@oe@26-8-2013 1000010002060@unknown@formal@none@1@S@DOM implementations tend to be ⌊>memory>⌋ intensive, as they generally require the entire document to be loaded into memory and constructed as a tree of objects before access is allowed.@@@@1@30@@oe@26-8-2013 1000010002070@unknown@formal@none@1@S@DOM is supported in Java by several packages that usually come with the standard libraries.@@@@1@15@@oe@26-8-2013 1000010002080@unknown@formal@none@1@S@As the DOM specification is regulated by the ⌊>World Wide Web Consortium>⌋, the main interfaces (Node, Document, etc.) are in the package org.w3c.dom.*, as well as some of the events and interfaces for other capabilities like serialization (output).@@@@1@38@@oe@26-8-2013 1000010002090@unknown@formal@none@1@S@The package com.sun.org.apache.xml.internal.serialize.* provides the serialization (output capacities) by implementing the appropriate interfaces, while the javax.xml.parsers.* package parses data to create DOM XML documents for manipulation.@@@@1@26@@oe@26-8-2013 1000010002100@unknown@formal@none@1@S@⌊=Non-extractive XML Processing API¦3=⌋@@@@1@4@@oe@26-8-2013 1000010002110@unknown@formal@none@1@S@Non-extractive XML Processing API is a new and emerging category of parsers that aim to overcome the fundamental limitations of DOM and SAX.@@@@1@23@@oe@26-8-2013 1000010002120@unknown@formal@none@1@S@The most representative is VTD-XML, which abolishes the object-oriented modeling of XML hierarchy and instead uses 64-bit Virtual Token Descriptors (encoding offsets, lengths, depths, and types) of XML tokens.@@@@1@29@@oe@26-8-2013 1000010002130@unknown@formal@none@1@S@VTD-XML's approach enables a number of interesting features/enhancements, such as high performance, low memory usage [8], ASIC implementation [9], incremental update [10], and native XML indexing [11] [12].@@@@1@28@@oe@26-8-2013 1000010002140@unknown@formal@none@1@S@⌊=Transformation engines and filters¦3=⌋@@@@1@4@@oe@26-8-2013 1000010002150@unknown@formal@none@1@S@A ⌊>filter>⌋ in the ⌊>Extensible Stylesheet Language>⌋ (XSL) family can transform an XML file for ⌊>display>⌋ing or ⌊>print>⌋ing.@@@@1@18@@oe@26-8-2013 1000010002160@unknown@formal@none@1@S@⌊•⌊#⌊∗⌊>XSL-FO>⌋∗⌋ is a declarative, XML-based ⌊>page layout>⌋ language.@@@@1@8@@oe@26-8-2013 1000010002170@unknown@formal@none@1@S@An XSL-FO processor can be used to convert an XSL-FO document into another non-XML format, such as ⌊>PDF>⌋.#⌋@@@@1@18@@oe@26-8-2013 1000010002180@unknown@formal@none@1@S@⌊#⌊∗⌊>XSLT>⌋∗⌋ is a declarative, XML-based document transformation language.@@@@1@8@@oe@26-8-2013 1000010002190@unknown@formal@none@1@S@An XSLT processor can use an XSLT ⌊/stylesheet/⌋ as a guide for the conversion of the data tree represented by one XML document into another tree that can then be ⌊>serialize>⌋d as XML, HTML, plain text, or any other format supported by the processor.#⌋@@@@1@44@@oe@26-8-2013 1000010002200@unknown@formal@none@1@S@⌊#⌊∗⌊>XQuery>⌋∗⌋ is a W3C language for ⌊>query>⌋ing, constructing and transforming XML data.#⌋@@@@1@12@@oe@26-8-2013 1000010002210@unknown@formal@none@1@S@⌊#⌊∗⌊>XPath>⌋∗⌋ is a DOM-like node tree ⌊>data model>⌋ and ⌊>path expression>⌋ language for selecting data within XML documents.@@@@1@18@@oe@26-8-2013 1000010002220@unknown@formal@none@1@S@XSL-FO, XSLT and XQuery all make use of XPath.@@@@1@9@@oe@26-8-2013 1000010002230@unknown@formal@none@1@S@XPath also includes a useful ⌊>function library>⌋.#⌋•⌋@@@@1@7@@oe@26-8-2013 1000010002240@unknown@formal@none@1@S@⌊=Pull parsing¦3=⌋@@@@1@2@@oe@26-8-2013 1000010002250@unknown@formal@none@1@S@Pull parsing treats the document as a series of items which are read in sequence using the Iterator design pattern.@@@@1@20@@oe@26-8-2013 1000010002260@unknown@formal@none@1@S@This allows for writing of ⌊>recursive-descent parsers>⌋ in which the structure of the code performing the parsing mirrors the structure of the XML being parsed, and intermediate parsed results can be used and accessed as local variables within the methods performing the parsing, or passed down (as method parameters) into lower-level methods, or returned (as method return values) to higher-level methods.@@@@1@61@@oe@26-8-2013 1000010002270@unknown@formal@none@1@S@Examples of pull parsers include ⌊>StAX>⌋ in the ⌊>Java>⌋ programming language, SimpleXML in PHP and System.Xml.XmlReader in .NET.@@@@1@18@@oe@26-8-2013 1000010002280@unknown@formal@none@1@S@A pull parser creates an iterator that sequentially visits the various elements, attributes, and data in an XML document.@@@@1@19@@oe@26-8-2013 1000010002290@unknown@formal@none@1@S@Code which uses this 'iterator' can test the current item (to tell, for example, whether it is a start or end element, or text), and inspect its attributes (local name, namespace, values of XML attributes, value of text, etc.), and can also move the iterator to the 'next' item.@@@@1@49@@oe@26-8-2013 1000010002300@unknown@formal@none@1@S@The code can thus extract information from the document as it traverses it.@@@@1@13@@oe@26-8-2013 1000010002310@unknown@formal@none@1@S@The recursive-descent approach tends to lend itself to keeping data as typed local variables in the code doing the parsing, while SAX, for instance, typically requires a parser to manually maintain intermediate data within a stack of elements which are parent elements of the element being parsed.@@@@1@47@@oe@26-8-2013 1000010002320@unknown@formal@none@1@S@Pull-parsing code can be more straightforward to understand and maintain than SAX parsing code.@@@@1@14@@oe@26-8-2013 1000010002330@unknown@formal@none@1@S@⌊=Data binding¦3=⌋@@@@1@2@@oe@26-8-2013 1000010002340@unknown@formal@none@1@S@Another form of XML Processing API is ⌊>data binding>⌋, where XML data is made available as a custom, strongly typed programming language data structure, in contrast to the interface-oriented DOM.@@@@1@30@@oe@26-8-2013 1000010002350@unknown@formal@none@1@S@Example data binding systems include the ⌊>Java>⌋ ⌊>Architecture>⌋ for XML Binding (⌊>JAXB>⌋).@@@@1@12@@oe@26-8-2013 1000010002360@unknown@formal@none@1@S@⌊=Specific XML applications and editors¦3=⌋@@@@1@5@@oe@26-8-2013 1000010002370@unknown@formal@none@1@S@The ⌊>native file format>⌋ of ⌊>OpenOffice.org>⌋, ⌊>AbiWord>⌋, and ⌊>Apple>⌋'s ⌊>iWork>⌋ applications is XML.@@@@1@13@@oe@26-8-2013 1000010002380@unknown@formal@none@1@S@Some parts of ⌊>Microsoft Office>⌋ 2007 are also able to edit XML files with a user-supplied schema (but not a DTD), and Microsoft has released a file format compatibility kit for Office 2003 that allows previous versions of Office to save in the new XML based format.@@@@1@47@@oe@26-8-2013 1000010002390@unknown@formal@none@1@S@There are dozens of other ⌊>XML editor>⌋s available.@@@@1@8@@oe@26-8-2013 1000010002400@unknown@formal@none@1@S@⌊=History¦2=⌋@@@@1@1@@oe@26-8-2013 1000010002410@unknown@formal@none@1@S@The versatility of ⌊>SGML>⌋ for dynamic information display was understood by early digital media publishers in the late 1980s prior to the rise of the Internet.@@@@1@26@@oe@26-8-2013 1000010002420@unknown@formal@none@1@S@By the mid-1990s some practitioners of SGML had gained experience with the then-new ⌊>World Wide Web>⌋, and believed that SGML offered solutions to some of the problems the Web was likely to face as it grew.@@@@1@36@@oe@26-8-2013 1000010002430@unknown@formal@none@1@S@⌊>Dan Connolly>⌋ added SGML to the list of W3C's activities when he joined the staff in 1995; work began in mid-1996 when ⌊>Jon Bosak>⌋ developed a charter and recruited collaborators.@@@@1@30@@oe@26-8-2013 1000010002440@unknown@formal@none@1@S@Bosak was well connected in the small community of people who had experience both in SGML and the Web.@@@@1@19@@oe@26-8-2013 1000010002450@unknown@formal@none@1@S@He received support in his efforts from ⌊>Microsoft>⌋.@@@@1@8@@oe@26-8-2013 1000010002460@unknown@formal@none@1@S@XML was compiled by a ⌊>working group>⌋ of eleven members, supported by an (approximately) 150-member Interest Group.@@@@1@17@@oe@26-8-2013 1000010002470@unknown@formal@none@1@S@Technical debate took place on the Interest Group mailing list and issues were resolved by consensus or, when that failed, majority vote of the Working Group.@@@@1@26@@oe@26-8-2013 1000010002480@unknown@formal@none@1@S@A record of design decisions and their rationales was compiled by ⌊>Michael Sperberg-McQueen>⌋ on December 4th 1997.@@@@1@17@@oe@26-8-2013 1000010002490@unknown@formal@none@1@S@⌊>James Clark>⌋ served as Technical Lead of the Working Group, notably contributing the empty-element "<empty/>" syntax and the name "XML".@@@@1@20@@oe@26-8-2013 1000010002500@unknown@formal@none@1@S@Other names that had been put forward for consideration included "MAGMA" (Minimal Architecture for Generalized Markup Applications), "SLIM" (Structured Language for Internet Markup) and "MGML" (Minimal Generalized Markup Language).@@@@1@29@@oe@26-8-2013 1000010002510@unknown@formal@none@1@S@The co-editors of the specification were originally ⌊>Tim Bray>⌋ and ⌊>Michael Sperberg-McQueen>⌋.@@@@1@12@@oe@26-8-2013 1000010002520@unknown@formal@none@1@S@Halfway through the project Bray accepted a consulting engagement with ⌊>Netscape>⌋, provoking vociferous protests from Microsoft.@@@@1@16@@oe@26-8-2013 1000010002530@unknown@formal@none@1@S@Bray was temporarily asked to resign the editorship.@@@@1@8@@oe@26-8-2013 1000010002540@unknown@formal@none@1@S@This led to intense dispute in the Working Group, eventually solved by the appointment of Microsoft's ⌊>Jean Paoli>⌋ as a third co-editor.@@@@1@22@@oe@26-8-2013 1000010002550@unknown@formal@none@1@S@The XML Working Group never met face-to-face; the design was accomplished using a combination of email and weekly teleconferences.@@@@1@19@@oe@26-8-2013 1000010002560@unknown@formal@none@1@S@The major design decisions were reached in twenty weeks of intense work between July and November of 1996, when the first Working Draft of an XML specification was published.@@@@1@29@@oe@26-8-2013 1000010002570@unknown@formal@none@1@S@Further design work continued through ⌊>1997>⌋, and XML 1.0 became a ⌊>W3C>⌋ Recommendation on ⌊>February 10>⌋, ⌊>1998>⌋.@@@@1@17@@oe@26-8-2013 1000010002580@unknown@formal@none@1@S@XML 1.0 achieved the Working Group's goals of Internet usability, general-purpose usability, SGML compatibility, facilitation of easy development of processing software, minimization of optional features, legibility, formality, conciseness, and ease of authoring.@@@@1@32@@oe@26-8-2013 1000010002590@unknown@formal@none@1@S@Like its antecedent SGML, XML allows for some redundant syntactic constructs and includes repetition of element identifiers.@@@@1@17@@oe@26-8-2013 1000010002600@unknown@formal@none@1@S@In these respects, terseness was not considered essential in its structure.@@@@1@11@@oe@26-8-2013 1000010002610@unknown@formal@none@1@S@⌊=Sources¦3=⌋@@@@1@1@@oe@26-8-2013 1000010002620@unknown@formal@none@1@S@XML is a profile of an ISO standard ⌊>SGML>⌋, and most of XML comes from SGML unchanged.@@@@1@17@@oe@26-8-2013 1000010002630@unknown@formal@none@1@S@From SGML comes the separation of logical and physical structures (elements and entities), the availability of grammar-based validation (DTDs), the separation of data and metadata (elements and attributes), mixed content, the separation of processing from representation (processing instructions), and the default angle-bracket syntax.@@@@1@43@@oe@26-8-2013 1000010002640@unknown@formal@none@1@S@Removed were the SGML Declaration (XML has a fixed delimiter set and adopts ⌊>Unicode>⌋ as the document ⌊>character set>⌋).@@@@1@19@@oe@26-8-2013 1000010002650@unknown@formal@none@1@S@Other sources of technology for XML were the ⌊>Text Encoding Initiative>⌋ (TEI), which defined a profile of SGML for use as a 'transfer syntax'; ⌊>HTML>⌋, in which elements were synchronous with their resource, the separation of document character set from resource encoding, the xml:lang attribute, and the ⌊>HTTP>⌋ notion that metadata accompanied the resource rather than being needed at the declaration of a link; and the Extended Reference Concrete Syntax (ERCS), from which XML 1.0's naming rules were taken, and which had introduced hexadecimal numeric character references and the concept of references to make available all Unicode characters.@@@@1@98@@oe@26-8-2013 1000010002660@unknown@formal@none@1@S@Ideas that developed during discussion which were novel in XML, were the algorithm for encoding detection and the encoding header, the processing instruction target, the xml:space attribute, and the new close delimiter for empty-element tags.@@@@1@35@@oe@26-8-2013 1000010002670@unknown@formal@none@1@S@⌊=Versions¦3=⌋@@@@1@1@@oe@26-8-2013 1000010002680@unknown@formal@none@1@S@There are two current versions of XML.@@@@1@7@@oe@26-8-2013 1000010002690@unknown@formal@none@1@S@The first, ⌊/XML 1.0/⌋, was initially defined in ⌊>1998>⌋.@@@@1@9@@oe@26-8-2013 1000010002700@unknown@formal@none@1@S@It has undergone minor revisions since then, without being given a new version number, and is currently in its fourth edition, as published on ⌊>August 16>⌋, ⌊>2006>⌋.@@@@1@27@@oe@26-8-2013 1000010002710@unknown@formal@none@1@S@It is widely implemented and still recommended for general use.@@@@1@10@@oe@26-8-2013 1000010002720@unknown@formal@none@1@S@The second, ⌊/XML 1.1/⌋, was initially published on ⌊>February 4>⌋, ⌊>2004>⌋, the same day as XML 1.0 Third Edition, and is currently in its second edition, as published on ⌊>August 16>⌋, ⌊>2006>⌋.@@@@1@32@@oe@26-8-2013 1000010002730@unknown@formal@none@1@S@It contains features — some contentious — that are intended to make XML easier to use in certain cases - mainly enabling the use of line-ending characters used on ⌊>EBCDIC>⌋ platforms, and the use of scripts and characters absent from Unicode 2.0.@@@@1@42@@oe@26-8-2013 1000010002740@unknown@formal@none@1@S@XML 1.1 is not very widely implemented and is recommended for use only by those who need its unique features.@@@@1@20@@oe@26-8-2013 1000010002750@unknown@formal@none@1@S@XML 1.0 and XML 1.1 differ in the requirements of characters used for element and attribute names: XML 1.0 only allows characters which are defined in Unicode 2.0, which includes most world scripts, but excludes those which were added in later Unicode versions.@@@@1@43@@oe@26-8-2013 1000010002760@unknown@formal@none@1@S@Among the excluded scripts are ⌊>Mongolian>⌋, ⌊>Cambodian>⌋, ⌊>Amharic>⌋, ⌊>Burmese>⌋, and others.@@@@1@11@@oe@26-8-2013 1000010002770@unknown@formal@none@1@S@Almost any Unicode character can be used in the character data and attribute values of an XML 1.1 document, even if the character is not defined, aside from having a code point, in the current version of Unicode.@@@@1@38@@oe@26-8-2013 1000010002780@unknown@formal@none@1@S@The approach in XML 1.1 is that only certain characters are forbidden, and everything else is allowed, whereas in XML 1.0, only certain characters are explicitly allowed, thus XML 1.0 cannot accommodate the addition of characters in future versions of Unicode.@@@@1@41@@oe@26-8-2013 1000010002790@unknown@formal@none@1@S@In character data and attribute values, XML 1.1 allows the use of more ⌊>control character>⌋s than XML 1.0, but, for "robustness", most of the control characters introduced in XML 1.1 must be expressed as numeric character references.@@@@1@37@@oe@26-8-2013 1000010002800@unknown@formal@none@1@S@Among the supported control characters in XML 1.1 are two line break codes that must be treated as whitespace.@@@@1@19@@oe@26-8-2013 1000010002810@unknown@formal@none@1@S@Whitespace characters are the only control codes that can be written directly.@@@@1@12@@oe@26-8-2013 1000010002820@unknown@formal@none@1@S@There are also discussions on an XML 2.0, although it remains to be seen ⌊πif such will ever come about. ⌊> XML-SW>⌋ (SW for ⌊>skunk works>⌋), written by one of the original developers of XML, contains some proposals for what an XML 2.0 might look like: elimination of DTDs from syntax, integration of ⌊>namespace>⌋s, ⌊>XML Base>⌋ and ⌊>XML Information Set>⌋ (⌊/infoset/⌋) into the base standard.π⌋@@@@1@65@@oe@26-8-2013 1000010002830@unknown@formal@none@1@S@The World Wide Web Consortium also has an XML Binary Characterization Working Group doing preliminary research into use cases and properties for a binary encoding of the XML infoset.@@@@1@29@@oe@26-8-2013 1000010002840@unknown@formal@none@1@S@The working group is not chartered to produce any official standards.@@@@1@11@@oe@26-8-2013 1000010002850@unknown@formal@none@1@S@Since XML is by definition text-based, ITU-T and ISO are using the name ⌊/⌊>Fast Infoset>⌋/⌋ for their own binary infoset to avoid confusion (see ITU-T Rec. X.891 | ISO/IEC 24824-1).@@@@1@30@@oe@26-8-2013 1000010002860@unknown@formal@none@1@S@⌊=Patent claims¦3=⌋@@@@1@2@@oe@26-8-2013 1000010002870@unknown@formal@none@1@S@In October 2005 the small company ⌊>Scientigo>⌋ publicly asserted that two of its patents, ⌊> U.S. Patent 5842213>⌋ and ⌊> U.S. Patent 6393426>⌋, apply to the use of XML.@@@@1@29@@oe@26-8-2013 1000010002880@unknown@formal@none@1@S@The patents cover the "modeling, storage and transfer [of data] in a particular ⌊/non-hierarchical/⌋, non-integrated neutral form", according to their applications, which were filed in 1997 and 1999.@@@@1@28@@oe@26-8-2013 1000010002890@unknown@formal@none@1@S@Scientigo CEO ⌊>Doyal Bryant>⌋ expressed a desire to "monetize" the patents but stated that the company was "not interested in having us against the world."@@@@1@25@@oe@26-8-2013 1000010002900@unknown@formal@none@1@S@He said that Scientigo was discussing the patents with several large corporations.@@@@1@12@@oe@26-8-2013 1000010002910@unknown@formal@none@1@S@XML users and independent experts responded to Scientigo's claims with widespread skepticism and criticism.@@@@1@14@@oe@26-8-2013 1000010002920@unknown@formal@none@1@S@Some derided the company as a ⌊>patent troll>⌋.@@@@1@8@@oe@26-8-2013 1000010002930@unknown@formal@none@1@S@⌊>Tim Bray>⌋ described any claims that the patents covered@@@@1@9@@oe@26-8-2013