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Encyclopedia > Cascading Style Sheets
Cascading Style Sheets
2.5in
File extension .css
MIME type text/css
Developed by World Wide Web Consortium
Type of format Stylesheet language
HTML
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CSS

Cascading Style Sheets
Comparison of layout engines (CSS)
CSS framework
CSS Zen Garden
CSSTidy
Tableless web design CSS is an abbreviation more often associated with Cascading Style Sheets but it may also refer to: In computing Central Structure Store, in the PHIGS 3D API. Closed source software. ... Image File history File links CSS.svg‎ sample css file from the dreftymac ImageNode series see http://en. ... A filename extension is a suffix to the name of a computer file applied to indicate its type. ... For mime as an art form, see mime artist. ... WWWC redirects here. ... A stylesheet language is a computer language used to describe the presentation of structured documents. ... HTML, an initialism of HyperText Markup Language, is the predominant markup language for web pages. ... HTML has been in use since 1991, but HTML 4. ... Dynamic HTML or DHTML is a collection of technologies used together to create interactive and animated web sites by using a combination of a static markup language (such as HTML), a client-side scripting language (such as JavaScript), a presentation definition language (Cascading Style Sheets, CSS), and the Document Object... In HTML and XHTML, a font face or font family is the typeface that is applied to some text. ... An HTML editor is a software application for creating web pages. ... In computing, an HTML element indicates structure in an HTML document and a way of hierarchically arranging content. ... The W3C HTML standard includes support for client-side scripting. ... This article or section is incomplete and may require expansion and/or cleanup. ... This article or section is incomplete and may require expansion and/or cleanup. ... Quirks mode refers to a technique used by some web browsers to maintain backwards compatibility with web pages designed for older browsers. ... It has been suggested that Tableless web design be merged into this article or section. ... Web pages authored using hypertext markup language (HTML) may contain multilingual text represented with the Unicode universal character set. ... WWWC redirects here. ... The following tables compare general and technical information for a number of web browsers. ... Web colors are colors used in designing web pages, and the methods for describing and specifying those colors. ... 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. ... The following tables compare XHTML compatibility and support for a number of layout engines. ... // The following tables compare CSS compatibility and support for a number of layout engines. ... A CSS framework is a library that is meant to allow for easier, more standards-compliant styling of a webpage using the Cascading Style Sheets language. ... CSS Zen Garden is an influential website developers resource. ... Tableless Web design (or tableless web layout) is a method of web design and development without using HTML tables for page layout control purposes. ...

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In web development, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. Its most common application is to style web pages written in HTML and XHTML, but the language can be applied to any kind of XML document, including SVG and XUL. Web development is a broad term for any activities related to developing a web site for the World Wide Web or an intranet. ... A stylesheet language is a computer language used to describe the presentation of structured documents. ... A specialized markup language using SGML is used to write the electronic version of the Oxford English Dictionary. ... A screenshot of a web page. ... HTML, an initialism of HyperText Markup Language, is the predominant markup language for web pages. ... 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. ... The Extensible Markup Language (XML) is a general-purpose markup language. ... SVG redirects here. ... XUL (pronounced zool ()), the XML User Interface Language, is an XML user interface markup language developed by the Mozilla project for use in its cross-platform applications, such as Firefox. ...


CSS is used to help readers of web pages to define colors, fonts, layout, and other aspects of document presentation. It is designed primarily to enable the separation of document content (written in HTML or a similar markup language) from document presentation (written in CSS). This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, and reduce complexity and repetition in the structural content. CSS can also allow the same markup page to be presented in different styles for different rendering methods, such as on-screen, in print, by voice (when read out by a speech-based browser or screen reader) and on Braille-based, tactile devices. CSS specifies a priority scheme to determine which style rules apply if more than one rule matches against a particular element. In this so-called cascade, priorities or weights are calculated and assigned to rules, so that the results are predictable. Color is an important part of the visual arts. ... “Font” redirects here. ... Layout, in publishing, is the process of arranging editorial content, advertising, graphics and other information in a manner that creates an effective presentation. ... It has been suggested that Easy Access be merged into this article or section. ... A screen reader is a software application that attempts to identify and interpret what is being displayed on the screen. ... Listen to this article ( info/dl) This audio file was created from a revision dated 2006-09-06, and may not reflect subsequent edits to the article. ... Tactition is the sense of pressure perception. ... A cascade is a term for a waterfall, or series of waterfalls, and is applied abstractly to many different concepts involving a series of steps or effects that follow one after the other. ...


The CSS specifications are maintained by the World Wide Web Consortium (W3C). Internet media type (MIME type) text/css is registered for use with CSS by RFC 2318 (March 1998). WWWC redirects here. ... For mime as an art form, see mime artist. ...

Contents

Syntax

CSS has a simple syntax, and uses a number of English keywords to specify the names of various style properties. For other uses, see Syntax (disambiguation). ...


A style sheet consists of a list of rules. Each rule or rule-set consists of one or more selectors and a declaration block. A declaration-block consists of a list of semicolon-separated declarations in curly braces. Each declaration itself consists of a property, a colon (:), a value, then a semi-colon (;).[1]


In CSS, selectors are used to declare which elements a style applies to, a kind of match expression. Selectors may apply to all elements of a specific type, or only those elements which match a certain attribute; elements may be matched depending on how they are placed relative to each other in the markup code, or on how they are nested within the document object model. Hierarchy of objects in an example HTML DOM - Document Object Model The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ...


In addition to these, a set of pseudo-classes can be used to define further behavior. Probably the best-known of these is :hover, which applies a style only when the user 'points to' the visible element, usually by holding the mouse cursor over it. It is appended to a selector as in a:hover or #elementid:hover. Other pseudo-classes and pseudo-elements are, for example, :first-line, :visited or :before. A special pseudo-class is :lang(c), "c".


A pseudo-class selects entire elements, such as :link or :visited, whereas a pseudo-element makes a selection that may consist of partial elements, such as :first-line or :first-letter.


Selectors may be combined in other ways too, especially in CSS 2.1, to achieve greater specificity and flexibility.[2]


Use of CSS

Prior to CSS, nearly all of the presentational attributes of HTML documents were contained within the HTML markup; all font colors, background styles, element alignments, borders and sizes had to be explicitly described, often repeatedly, within the HTML. CSS allows authors to move much of that information to a separate stylesheet resulting in considerably simpler HTML markup.


Headings (h1 elements), sub-headings (h2), sub-sub-headings (h3), etc., are defined structurally using HTML. In print and on the screen, choice of font, size, color and emphasis for these elements is presentational. A heading is used to provide hierarchical information about other information. ... “Font” redirects here. ... Point, in typography, may also refer to a dot grapheme (e. ... Color is an important part of the visual arts. ... Bold and Boldface redirect here. ...


Prior to CSS, document authors who wanted to assign such typographic characteristics to, say, all h2 headings had to use the HTML font and other presentational elements for each occurrence of that heading type. The additional presentational markup in the HTML made documents more complex, and generally more difficult to maintain. In CSS, presentation is separated from structure. In print, CSS can define color, font, text alignment, size, borders, spacing, layout and many other typographic characteristics. It can do so independently for on-screen and printed views. CSS also defines non-visual styles such as the speed and emphasis with which text is read out by aural text readers. The W3C now considers the advantages of CSS for defining all aspects of the presentation of HTML pages to be superior to other methods. It has therefore deprecated the use of all the original presentational HTML markup. A specimen of roman typefaces by William Caslon Typography is the art and techniques of type design, modifying type glyphs, and arranging type. ... The World Wide Web Consortium (W3C) is a consortium that produces standards—recommendations, as they call them—for the World Wide Web. ... Look up Deprecation in Wiktionary, the free dictionary. ...


Style sheet sources

CSS information can be provided by various sources. CSS style information can be either attached as a separate document or embedded in the HTML document. Multiple style sheets can be imported, and alternative style sheets can be specified so that the user can choose between them. Different styles can be applied depending on the output device being used; for example, the screen version can be quite different from the printed version, so that authors can tailor the presentation appropriately for each medium.

  • Author styles (style information provided by the web page author), in the form of
    • external stylesheets, i.e. a separate CSS-file referenced from the document
    • embedded style, blocks of CSS information inside the HTML document itself
    • inline styles, inside the HTML document, style information on a single element, specified using the "style" attribute.
  • User style
    • a local CSS-file specified by the user using options in the web browser, and acting as an override, to be applied to all documents.
  • User agent style
    • the default style sheet applied by the user agent, e.g. the browser's default presentation of elements.

One of the goals of CSS is also to allow users a greater degree of control over presentation; those who find the red italic headings difficult to read may apply other style sheets to the document. Depending on their browser and the web site, a user may choose from various stylesheets provided by the designers, may remove all added style and view the site using their browser's default styling or may perhaps override just the red italic heading style without altering other attributes. A user agent is the client application used with a particular network protocol; the phrase is most commonly used in reference to those which access the World Wide Web. ...


File highlightheaders.css containing:

 h1 { color: white; background: orange !important; } h2 { color: white; background: green !important; } 

Such a file is stored locally and is applicable if that has been specified in the browser options. "!important" means that it prevails over the author specifications.


History

Style sheets have existed in one form or another since the beginnings of SGML in the 1970s. Cascading Style Sheets were developed as a means for creating a consistent approach to providing style information for web documents. The Standard Generalized Markup Language (SGML) is a metalanguage in which one can define markup languages for documents. ... Year 1970 (MCMLXX) was a common year starting on Thursday (link shows full calendar) of the Gregorian calendar. ...


As HTML grew, it came to encompass a wider variety of stylistic capabilities to meet the demands of web developers. This evolution gave the designer more control over site appearance but at the cost of HTML becoming more complex to write and maintain. Variations in web browser implementations made consistent site appearance difficult, and users had less control over how web content was displayed. Web development is a broad term for any activities related to developing a web site for the World Wide Web or an intranet. ... An example of a Web browser (Mozilla Firefox) A web browser is a software application that enables a user to display and interact with text, images, videos, music and other information typically located on a Web page at a website on the World Wide Web or a local area network. ...


To improve the capabilities of web presentation, nine different style sheet languages were proposed to the W3C's www-style mailing list. Of the nine proposals, two were chosen as the foundation for what became CSS: Cascading HTML Style Sheets (CHSS) and Stream-based Style Sheet Proposal (SSP). First, Håkon Wium Lie (now the CTO of Opera Software) proposed Cascading HTML Style Sheets (CHSS) in October 1994, a language which has some resemblance to today's CSS. Bert Bos was working on a browser called Argo which used its own style sheet language, Stream-based Style Sheet Proposal (SSP). Lie and Bos worked together to develop the CSS standard (the 'H' was removed from the name because these style sheets could be applied to other markup languages besides HTML). HÃ¥kon Wium Lie (born 1965 in Norway) is, as of 2004, presently Chief Technology Officer of Opera Software, where he has worked since 1999. ... A chief technical officer or chief technology officer (abbreviated as CTO) is an executive position whose holder is focused on scientific and technical issues within a company. ... Logo of Opera Software. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... Bert Bos is a computer scientist. ... Argo was part of a project to make the Internet accessible to scholars in the Humanities at the University of Groningen. ...


Unlike existing style languages like DSSSL and FOSI, CSS allowed a document's style to be influenced by multiple style sheets. One style sheet could inherit or "cascade" from another, permitting a mixture of stylistic preferences controlled equally by the site designer and user. Document Style Semantics and Specification Language (DSSSL) is a language for specifying stylesheets for SGML documents, based on a subset of the Scheme programming language. ... In computing, FOSI is a style sheet language for SGML and, later, XML. It stands for Formatted Output Specification Instance. ... This article or section does not cite any references or sources. ...


Håkon's proposal was presented at the "Mosaic and the Web" conference in Chicago, Illinois in 1994, and again with Bert Bos in 1995. Around this time, the World Wide Web Consortium was being established; the W3C took an interest in the development of CSS, and it organized a workshop toward that end chaired by Steven Pemberton. This resulted in W3C adding work on CSS to the deliverables of the HTML editorial review board (ERB). Håkon and Bert were the primary technical staff on this aspect of the project, with additional members, including Thomas Reardon of Microsoft, participating as well. By the end of 1996, CSS was ready to become official, and the CSS level 1 Recommendation was published in December. Flag Seal Nickname: The Windy City Motto: Urbs In Horto (Latin: City in a Garden), I Will Location Location in Chicagoland and northern Illinois Coordinates , Government Country State Counties United States Illinois Cook, DuPage Mayor Richard M. Daley (D) Geographical characteristics Area     City 606. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... Year 1995 (MCMXCV) was a common year starting on Sunday. ... Steven Pemberton (born February 19, 1953) is one of the developers of the ABC programming language and of the Views system. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ...


Development of HTML, CSS, and the DOM had all been taking place in one group, the HTML Editorial Review Board (ERB). Early in 1997, the ERB was split into three working groups: HTML Working group, chaired by Dan Connolly of W3C; DOM Working group, chaired by Lauren Wood of SoftQuad; and CSS Working group, chaired by Chris Lilley of W3C. Hierarchy of objects in an example HTML DOM - Document Object Model The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ... For the band, see 1997 (band). ... Wikipedia does not have an article with this exact name. ... Dan Connolly received a B.S. in Computer Science from the University of Texas at Austin in 1990. ... SoftQuad Software is best known for its HoTMetaL HTML editing software. ... Chris Lilley (born 1959 in the UK) was educated at Broxburn Academy in West Lothian, Scotland. ...


The CSS Working Group began tackling issues that had not been addressed with CSS level 1, resulting in the creation of CSS level 2 on November 4, 1997. It was published as a W3C Recommendation on May 12, 1998. CSS level 3, which was started in 1998, is still under development as of 2008. is the 308th day of the year (309th in leap years) in the Gregorian calendar. ... For the band, see 1997 (band). ... is the 132nd day of the year (133rd in leap years) in the Gregorian calendar. ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... 2008 (MMVIII) will be a leap year starting on Tuesday of the Gregorian calendar. ...


In 2005 the CSS Working Groups decided to enforce the requirements for standards more strictly. This meant that already published standards like CSS 2.1, CSS 3 Selectors and CSS 3 Text were pulled back from Candidate Recommendation to Working Draft level. Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...


Difficulty with adoption

Although the CSS1 specification was completed in 1996 and Microsoft's Internet Explorer 3 was released in that year featuring some limited support for CSS, it would be more than three years before any web browser achieved near-full implementation of the specification. Internet Explorer 5.0 for the Macintosh, shipped in March of 2000, was the first browser to have full (better than 99 percent) CSS1 support, surpassing Opera, which had been the leader since its introduction of CSS support fifteen months earlier. Other browsers followed soon afterwards, and many of them additionally implemented parts of CSS2. As of July 2006, no browser has fully implemented CSS2, with implementation levels varying (see Comparison of layout engines (CSS)). Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ... Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ... The first Macintosh computer, introduced in 1984, upgraded to a 512K Fat Mac. The Macintosh or Mac, is a line of personal computers designed, developed, manufactured, and marketed by Apple Computer. ... Opera is an Internet suite which handles common internet-related tasks, including visiting web sites, sending and receiving e-mail messages, managing contacts, and online chat. ... 2006 is a common year starting on Sunday of the Gregorian calendar. ... // The following tables compare CSS compatibility and support for a number of layout engines. ...


Even though early browsers such as Internet Explorer 3 and 4, and Netscape 4.x had support for CSS, it was typically incomplete and afflicted with serious bugs. This was a serious obstacle for the adoption of CSS. Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ... Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ... Netscape Navigator, also known as Netscape, was a proprietary web browser that was popular during the 1990s. ... A software bug is an error, flaw, mistake, failure, or fault in a computer program that prevents it from behaving as intended (e. ...


When later 'version 5' browsers began to offer a fairly full implementation of CSS, they were still incorrect in certain areas and were fraught with inconsistencies, bugs and other quirks. The proliferation of such CSS-related inconsistencies and even the variation in feature support has made it difficult for designers to achieve a consistent appearance across platforms. Some authors commonly resort to using some workarounds such as CSS hacks and CSS filters in order to obtain consistent results across web browsers and platforms. A workaround is a bypass of a recognized problem in a system. ... From Cascading Style Sheets: A CSS filter is a coding technique that aims to effectively hide or show parts of the CSS to different browsers, either by exploiting CSS-handling quirks or bugs in the browser or by taking advantage of lack of support for parts of the CSS specifications. ... In computing, a platform describes some sort of framework, either in hardware or software, which allows software to run. ...


Problems with browsers' patchy adoption of CSS along with errata in the original specification led the W3C to revise the CSS2 standard into CSS2.1, which may be regarded as something nearer to a working snapshot of current CSS support in HTML browsers. Some CSS2 properties which no browser had successfully implemented were dropped, and in a few cases, defined behaviours were changed to bring the standard into line with the predominant existing implementations. CSS2.1 became a Candidate Recommendation on February 25, 2004, but was pulled back to Working Draft status on June 13, 2005, and only returned to Candidate Recommendation status on July 19, 2007.


In the past, some web servers were configured to serve documents with the filename extension .css as mime type application/x-pointplus. At the time, the Net-Scene company was selling PointPlus Maker to convert PowerPoint files into Compact Slide Show files (using the .css extension) and web servers were configured to signal to client browsers that these .css files were x-pointplus media type. Since the plugin was listed in the directory for Netscape Navigator 3.0, the popular Netscape Enterprise Server was distributed with this mapping pre-configured. When reading external style sheets some web browsers try to compensate for the misconfigured web servers by treating the PointPlus media type as a text/css media type instead, but some comply with the media type and will not render the external CSS file as a style sheet. Power point redirects here. ... Netscape Navigator, also known as Netscape, was a proprietary web browser that was popular during the 1990s. ... Netscape Enterprise Server was a web server developed originally by Netscape Communications Corporation. ...


Variations

CSS has various levels and profiles. Each level of CSS builds upon the last, typically adding new features and typically denoted as CSS1, CSS2, and CSS3. Profiles are typically a subset of one or more levels of CSS built for a particular device or user interface. Currently there are profiles for mobile devices, printers, and television sets. Profiles should not be confused with media types which were added in CSS2.


The first CSS specification to become an official W3C Recommendation is CSS level 1, published in December 1996.[3] Among its capabilities are support for:

  • Font properties such as typeface and emphasis
  • Color of text, backgrounds, and other elements
  • Text attributes such as spacing between words, letters, and lines of text
  • Alignment of text, images, tables and other elements
  • Margin, border, padding, and positioning for most elements
  • Unique identification and generic classification of groups of attributes

The W3C maintains the CSS1 Recommendation.[4] “Font” redirects here. ... Color is an important part of the visual arts. ... This page is a candidate for speedy deletion. ... Table is a HTML tag for creating boxes on web pages and to display data in those boxes. ...


CSS level 2 was developed by the W3C and published as a Recommendation in May 1998. A superset of CSS1, CSS2 includes a number of new capabilities like absolute, relative, and fixed positioning of elements, the concept of media types, support for aural style sheets and bidirectional text, and new font properties such as shadows. The W3C maintains the CSS2 Recommendation.[5] The term positioning has more than one meaning: In marketing, see Positioning (marketing) For reader positioning, see Critical literacy (positioning) In telecommunications, see Positioning (telecommunications) In grappling, see Grappling position In editing, positioning may determine the allocation of text on a page Positioning is also the term for the careful...


CSS level 2 revision 1 or CSS 2.1 fixes errors in CSS2, removes poorly-supported features and adds already-implemented browser extensions to the specification. While it was a Candidate Recommendation for several months, on 15 June 2005 it was reverted to a working draft for further review.[6] It was returned to Candidate Recommendation status on 19 July 2007. is the 166th day of the year (167th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 200th day of the year (201st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ...


CSS level 3 is currently under development.[7] The W3C maintains a CSS3 progress report. As with the evolving XHTML specification, CSS3 is modularized and will consist of several separate Recommendations. An Introduction to CSS3 roadmap will be the starting point. Software engineering (SE) is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software. ... 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. ...


Browser support

A CSS filter[8] is a coding technique that aims to effectively hide or show parts of the CSS to different browsers, either by exploiting CSS-handling quirks or bugs in the browser, or by taking advantage of lack of support for parts of the CSS specifications. Using CSS filters, some designers have gone as far as delivering entirely different CSS to certain browsers in order to ensure that designs are rendered as expected. Because very early web browsers were either completely incapable of handling CSS, or render CSS very poorly, designers today often routinely use CSS filters that completely prevent these browsers from accessing any of the CSS. Internet Explorer support for CSS began with IE 3.0 and increased progressivly with each version. By 2008, the first Beta of Internet Explorer 8 offered support for CSS 2.1 in its best web standards mode. An example of parsing a mathematical expression. ... Windows Internet Explorer (formerly Microsoft Internet Explorer abbreviated MSIE), commonly abbreviated to IE, is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems starting in 1995. ... Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ... Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ...


An example of a well-known CSS browser bug is the Internet Explorer box model bug, where box widths are interpreted incorrectly in several versions of the browser, resulting in blocks which are too narrow when viewed in Internet Explorer, but correct in standards-compliant browsers. The bug can be avoided in Internet Explorer 6 by using the correct doctype in (X)HTML documents. CSS hacks and CSS filters are used to compensate for bugs such as this, just one of hundreds of CSS bugs that have been documented in various versions of Netscape, Mozilla Firefox, Opera, and Internet Explorer (including Internet Explorer 7)[9]. [1] The difference between the World Wide Web Consortiums width and Internet Explorers width of a block-level element The Internet Explorer box model bug is one of the best-known bugs in a popular implementation of Cascading Style Sheets (CSS). ... Internet Explorer, abbreviated IE or MSIE, is a proprietary web browser made by Microsoft and currently available as part of Microsoft Windows. ... A Document Type Declaration (DOCTYPE for short) defines what Document Type Definition an XML or SGML document complies to. ... From Cascading Style Sheets: A CSS filter is a coding technique that aims to effectively hide or show parts of the CSS to different browsers, either by exploiting CSS-handling quirks or bugs in the browser or by taking advantage of lack of support for parts of the CSS specifications. ... Netscape was a proprietary cross-platform Internet suite created by Netscape Communications Corporation and then in-house by AOL to continue the Netscape series after Netscape 6. ... Firefox redirects here. ... Opera is an Internet suite which handles common internet-related tasks, including visiting web sites, sending and receiving e-mail messages, managing contacts, and online chat. ... Windows Internet Explorer 7, commonly abbreviated IE7, is a web browser released by Microsoft in late 2006 for Windows Vista, Windows XP and Windows Server 2003. ...


Even when the availability of CSS-capable browsers made CSS a viable technology, the adoption of CSS was still held back by designers' struggles with browsers' incorrect CSS implementation and patchy CSS support. Even today, these problems continue to make the business of CSS design more complex and costly than it should be, and cross-browser testing remains a necessity. Other reasons for continuing non-adoption of CSS are: its perceived complexity, authors' lack of familiarity with CSS syntax and required techniques, poor support from authoring tools, the risks posed by inconsistency between browsers and the increased costs of testing.


Currently there is strong competition between Mozilla's Gecko layout engine, the WebKit layout engine used in Apple's Safari, the similar KHTML engine used in KDE's Konqueror browser, and Opera's Presto layout engine - each of them is leading in different aspects of CSS. As of 2007, Internet Explorer's Trident engine remains the worst at rendering CSS as judged by World Wide Web Consortium standards ([2] as linked from [3]). In April 2008 Internet Explorer 8 beta fixes many of these shortcomings and renders CSS 2.1. It nearly passes the ACID2 test. Mozilla was the official, public, original name of Mozilla Application Suite by the Mozilla Foundation, nowadays called SeaMonkey suite. ... Epiphany using Gecko to render the Wikipedia main page Gecko is the open source, free software web browser layout engine used in all Mozilla-branded software and its derivatives, including later Netscape releases. ... WebKit is an application framework included with Mac OS X v10. ... Apple Inc. ... Safari is a web browser developed by Apple Inc. ... Konqueror using KHTML to render the Wikipedia front page. ... For the NYSE stock ticker symbol KDE, see 4Kids Entertainment. ... Konqueror is a file manager, web browser and file viewer, which was developed as part of the K Desktop Environment (KDE) by volunteers and runs on most Unix-like operating systems. ... Presto is a layout engine for the Opera web browser developed by Opera Software. ... Trident (also known as MSHTML) is the name of the layout engine for the Microsoft Windows version of Internet Explorer. ... WWWC redirects here. ... The reference image for Acid2. ...


Limitations

Some noted disadvantages of using "pure" CSS include:

Inconsistent browser support 
Different browsers will render CSS layout differently as a result of browser bugs or lack of support for CSS features. For example Microsoft Internet Explorer, whose older versions, such as IE 6.0, implemented many CSS 2.0 properties in its own, incompatible way, misinterpreted a significant number of important properties, such as width, height, and float[10]. Numerous so-called CSS "hacks" must be implemented to achieve consistent layout among the most popular or commonly used browsers. Pixel precise layouts can sometimes be impossible to achieve across browsers.
Selectors are unable to ascend 
CSS offers no way to select a parent or ancestor of element that satisfies certain criteria. A more advanced selector scheme (such as XPath) would enable more sophisticated stylesheets. However, the major reasons for the CSS Working Group rejecting proposals for parent selectors are related to browser performance and incremental rendering issues.
One block declaration cannot explicitly inherit from another 
Inheritance of styles is performed by the browser based on the containment hierarchy of DOM elements and the specificity of the rule selectors, as suggested by the section 6.4.1 of the CSS2 specification.[11] Only the user of the blocks can refer to them by including class names into the class attribute of a DOM element.
Vertical control limitations 
While horizontal placement of elements is generally easy to control, vertical placement is frequently unintuitive, convoluted, or impossible. Simple tasks, such as centering an element vertically or getting a footer to be placed no higher than bottom of viewport, either require complicated and unintuitive style rules, or simple but widely unsupported rules.
Absence of expressions 
There is currently no ability to specify property values as simple expressions (such as margin-left: 10% - 3em + 4px;). This is useful in a variety of cases, such as calculating the size of columns subject to a contains on the sum of all columns. However, a working draft with a calc() value to address this limitation has been published by the CSS WG,[12] and Internet Explorer 5 and all later versions support a proprietary expression() statement,[13] with similar functionality.
Lack of orthogonality 
Multiple properties often end up doing the same job. For instance, position, display and float specify the placement model, and most of the time they cannot be combined meaningfully. A display: table-cell element cannot be floated or given position: relative, and an element with float: left should not react to changes of display. In addition, some properties are not defined in a flexible way that avoids creation of new properties. For example, you should use the "border-spacing" property on table element instead of the "margin-*" property on table cell elements. This is because according to the CSS specification, internal table elements do not have margins.
Margin collapsing 
Margin collapsing is, while well-documented and useful, also complicated and is frequently not expected by authors, and no simple side-effect-free way is available to control it.
Float containment 
CSS does not explicitly offer any property that would force an element to contain floats. Multiple properties offer this functionality as a side effect, but none of them are completely appropriate in all situations. As there will be an overflow when the elements, which is contained in a container, use float property. Generally, position: relative does solve this. Floats will be different according to the web browser size and resolution, but positions can not.
Lack of multiple backgrounds per element 
Highly graphical designs require several background images for every element, and CSS can support only one. Therefore, developers have to choose between adding redundant wrappers around document elements, or dropping the visual effect. This is partially addressed in the working draft of the CSS3 backgrounds module,[14] which is already supported in Safari and Konqueror.
Control of Element Shapes 
CSS currently only offers rectangular shapes. Rounded corners or other shapes may require non-semantic markup. However, this is addressed in the working draft of the CSS3 backgrounds module.[15]
Lack of Variables 
CSS contains no variables. This makes it necessary to do a "replace-all" when one desires to change a fundamental constant, such as the color scheme or various heights and widths. This may not even be possible to do in a reasonable way (consider the case where one wants to replace certain heights which are 50px, but not others which are also 50px; this would require very complicated regular expressions).
Lack of column declaration 
While possible in current CSS, layouts with multiple columns can be complex to implement. With the current CSS, the process is often done using floating elements which are often rendered differently by different browsers, different computer screen shapes, and different screen ratios set on standard monitors.
Cannot explicitly declare new scope independently of position 
Scoping rules for properties such as z-height look for the closest parent element with a position:absolute or position:relative attribute. This odd coupling has two undesired effects: 1) it is impossible to avoid declaring a new scope when one is forced to adjust an element's position, preventing one from using the desired scope of a parent element and 2) users are often not aware that they must declare position:relative or position:absolute on any element they want to act as "the new scope". Additionally, a bug in the Firefox browser prevents one from declaring table elements as a new css scope using position:relative (one can technically due so, but numerous graphical glitches result).

Windows Internet Explorer (formerly Microsoft Internet Explorer abbreviated MSIE), commonly abbreviated to IE, is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems starting in 1995. ... XPath (XML Path Language) is an expression language for addressing portions of an XML document, or for computing values (strings, numbers, or boolean values) based on the content of an XML document. ... A W3C Recommendation is the final stage of a ratification process of the W3C working group concerning the standard. ... A W3C Recommendation is the final stage of a ratification process of the W3C working group concerning the standard. ... A W3C Recommendation is the final stage of a ratification process of the W3C working group concerning the standard. ...

See also

The following is a list of stylesheet languages. ... CSS was suggested in 1994 by HÃ¥kon Wium Lie. ... // The following tables compare CSS compatibility and support for a number of layout engines. ... A CSS framework is a library that is meant to allow for easier, more standards-compliant styling of a webpage using the Cascading Style Sheets language. ... CSS Zen Garden is an influential website developers resource. ... HTML, an initialism of HyperText Markup Language, is the predominant markup language for web pages. ... Minify, in computer programming languages, is the process of removing all unnecessary characters from source code, with out changing its functionality. ... Tableless Web design (or tableless web layout) is a method of web design and development without using HTML tables for page layout control purposes. ... Look up validator in Wiktionary, the free dictionary. ... 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. ... ... The reference image for Acid2. ... W3Schools is a web developers portal, with tutorials and references of many different web development subjects, including HTML and JavaScript to name a few. ...

References

The World Wide Web Consortium (W3C) is a consortium that produces standards—recommendations, as they call them—for the World Wide Web. ... The World Wide Web Consortium (W3C) is a consortium that produces standards—recommendations, as they call them—for the World Wide Web. ... The World Wide Web Consortium (W3C) is a consortium that produces standards—recommendations, as they call them—for the World Wide Web. ... The World Wide Web Consortium (W3C) is a consortium that produces standards—recommendations, as they call them—for the World Wide Web. ... The World Wide Web Consortium (W3C) is a consortium that produces standards—recommendations, as they call them—for the World Wide Web. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 179th day of the year (180th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 179th day of the year (180th in leap years) in the Gregorian calendar. ...

Further reading

  • Eric A. Meyer: Cascading Style Sheets: The Definitive Guide, Third Edition, ISBN 0596527330
  • Eric A. Meyer: Cascading Style Sheets 2.0 Programmer's Reference, McGraw-Hill Osborne Media, ISBN 0-07-213178-0
  • Keith Schengili-Roberts: Core CSS, 2nd Edition, Prentice Hall, ISBN 0-13-009278-9
  • Cascading Style Sheets: Designing for the Web by Håkon Wium Lie and Bert Bos, ISBN 0-321-19312-1
  • The Zen of CSS Design (co-authored by CSS Zen Garden Owner, Dave Shea, and Molly E. Holzschlag), ISBN 0-321-30347-4
  • Eric Meyer On CSS, ISBN 0-7357-1245-X
  • More Eric Meyer On CSS, ISBN 0-7357-1425-8
  • Dan Cederholm: Web Standards Solutions, The Markup and Style Handbook, Friends of Ed, ISBN 1-59059-381-2 (paperback) (Author's site)
  • Kynn Bartlett: Teach Yourself CSS in 24 Hours, 2nd Edition, Sams Publishing, ISBN 0-672-32906-9 (book's companion site)
  • Cascading Style Sheets Cascading Style Sheets, PhD thesis, by Håkon Wium Lie - provides an authoritative historical reference of CSS
  • Jeffrey Zeldman: Designing With Web Standards, New Riders, ISBN 0-7357-1201-8 (paperback) (book's companion site)
  • Cascading Style Sheets: Separating Content from Presentation, (co-authored by Owen Briggs, Steven Champeon, Eric Costello, and Matt Patterson), Friends of Ed, ISBN 1-59059-231-X
  • Chris Davis' Variables in your CSS via PHP Variables in your CSS via PHP

Eric A. Meyer is the author of several well-known books on Cascading Style Sheets (CSS), a part of the HTML standard. ... Eric A. Meyer is the author of several well-known books on Cascading Style Sheets (CSS), a part of the HTML standard. ... Keith Schengili-Roberts is a long-time author on Internet technologies, beginning with his work for the magazines Toronto Computes! in the early 1990s and then The Computer Paper from the mid-1990s up until 2003. ... Dan Cederholm is a web designer, author, and speaker living in Salem, Massachusetts. ... Jeffrey Zeldman is a prominent lecturer and author on web design. ...

External links

Wikibooks
Wikibooks has a book on the topic of
Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... The Open Directory Project (ODP), also known as dmoz (from , its original domain name), is a multilingual open content directory of World Wide Web links owned by Netscape that is constructed and maintained by a community of volunteer editors. ... HowStuffWorks is a website created by Marshall Brain but now owned by the Convex Group. ... WWWC redirects here. ... A W3C Recommendation is the final stage of a ratification process of the W3C working group concerning the standard. ... Compound Document Format (CDF) is an electronic document format proposed to overcome perceived shortcomings in the Open Document Format. ... The Common Gateway Interface (CGI) is a standard protocol for interfacing external application software with an information server, commonly a web server. ... Hierarchy of objects in an example HTML DOM - Document Object Model The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ... HTML, an initialism of HyperText Markup Language, is the predominant markup language for web pages. ... Mathematical Markup Language (MathML) is an application of XML for describing mathematical notations and capturing both its structure and content. ... The Web Ontology Language (OWL) is a language for defining and instantiating Web ontologies. ... Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata model but which has come to be used as a general method of modeling information, through a variety of syntax formats. ... RDF Schema is a language for describing vocabularies in RDF. RDF Schema is a semantic extension of RDF. It provides mechanisms for describing groups of related resources and the relationships between these resources. ... Semantic Interpretation for Speech Recognition (SISR) defines the syntax and semantics of annotations to grammar rules in the Speech Recognition Grammar Specification (SRGS). ... SMIL (pronounced smile), the Synchronized Multimedia Integration Language, is a W3C recommended XML markup language for describing multimedia presentations. ... For other uses, see Soap (disambiguation). ... Speech Recognition Grammar Specification (SRGS) is an W3C recommendation that defines syntax for representing grammars for use in speech recognition so that developers can specify the words and patterns of words to be listened for by a speech recognizer. ... Speech Synthesis Markup Language (SSML) is an XML-based markup language for speech synthesis applications. ... SVG redirects here. ... Timed Text refers to the presentation of text media in synchrony with other media, such as audio and video. ... VoiceXML (VXML) is the W3Cs standard XML format for specifying interactive voice dialogues between a human and a computer. ... WSDL redirects here. ... XACML stands for eXtensible Access Control Markup Language. ... XForms is two things: 1. ... 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. ... The Extensible Markup Language (XML) is a general-purpose markup language. ... This page is a candidate for speedy deletion. ... www. ... XML Information Set (Infoset) is a W3C recommendation. ... This article is about the W3Cs XML Schema language. ... XML Signature (also called XMLDsig) is a W3C recommendation that defines an XML syntax for digital signatures. ... XPath (XML Path Language) is an expression language for addressing portions of an XML document, or for computing values (strings, numbers, or boolean values) based on the content of an XML document. ... XPointer is a system for addressing components of XML based internet media. ... XQuery is a query language (with some programming language features) that is designed to query collections of XML data. ... Diagram of the basic elements and process flow of Extensible Stylesheet Language Transformations. ... XSL Formatting Objects, or XSL-FO, is an XML markup language for document formatting which is most often used to generate PDFs. ... The eXtensible Stylesheet Language (XSL) is a family of transformation languages which allows one to describe how files encoded in the XML standard are to be formatted or transformed. ... The XML Linking Language, or XLink, is an XML markup language used for creating hyperlinks within XML documents. ... XHTML+SMIL is a W3C Note that describes an integration of SMIL semantics with XHTML and CSS. It is based generally upon the HTML+TIME submission. ... Call Control eXtensible Markup Language (CCXML) is an XML standard designed to provide telephony support to VXML. Where as VXML is designed to provide a VUI interface to a voice browser, CCXML is designed to inform the voice browser how to handle the telephony control of the voice channel. ... The curie (symbol Ci) is a former unit of radioactivity, defined as 3. ... InkML is a format to describe ink data input with an electronic pen or stylus. ... XFrames is an XML application being developed by the W3C for combining multiple documents together. ... Extensible Forms Description Language (XFDL) is a class of the Extensible Markup Language (XML) specified in World Wide Web Consortium (W3C) NOTE-XFDL-19980902, Extensible Forms Description Language (XFDL) 4. ... Web Integration Compound Document (WICD) is a W3C standard, based on the idea of integrating existing markup language formats in preference to inventing new markup. ... XHTML+MathML+SVG is a W3C Working Draft that describes an integration of MathML and SVG semantics with XHTML and CSS. W3C Working Draft Category: ... XBL or eXtensible Bindings Language is used to declare the behavior and look of XUL widgets and XML elements. ... HTML 5 is the fifth major revision of the core language of the World Wide Web, HTML. HTML 5 expressed in XML is called XHTML 5. ...

  Results from FactBites:
 
Cascading Style Sheets - Wikipedia, the free encyclopedia (3965 words)
CSS can also allow the same markup page to be presented in different styles for different rendering methods, such as on-screen, in print, by voice (when read out by a speech-based browser or screen reader) and on braille-based, tactile devices.
Style sheets have been around in one form or another since the beginnings of SGML in the 1970s.
Inheritance of styles is performed by the browser based on the containment hierarchy of DOM elements and the specificity of the rule selectors, as suggested by the section 6.4.1 of the CSS2 specification [2].
  More results at FactBites »

 
 

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