CSS – Cascading Style Sheets | Part 2

CSS – Cascading Style Sheets | Part 2

History of CSS

The concept of style sheet is a pioneer and the World Wide Web: the first web browser (WorldWideWeb, later renamed “Nexus”) allows you to format documents using what is TODAY ‘hui considered a “user stylesheet”. Similarly, the Viola browser in 1992 and Harmony in 1993 to use a similar mechanism to determine the rendering of fonts, colors or text alignment.

It is however not determined by the style author. The first implementations HTML does not include additional disclosures, there is increasing pressure so that browsers allow authors to determine for themselves the formatting of the website, in a step after publication printed electronics. In this context, in 1994-1995, the all-new Netscape introduced the first presentation of HTML elements on the initiative of Marc Andreessen, while concurrently the first proposals show delivery formats external styles: the “stylesheet proposition” Pei Wei (Viola creator), “Stylesheets for HTML” Robert Raisch (O’Reilly), and finally the “HTML Cascading Style Sheets (CHSS) to Håkon Wium Lie. The emergence of CSS responds to a desire to “offer an alternative to HTML evolution of a language to structure a presentation language”.

A third way of development is also open at the same time: the transformation language DSSSL SGML documents, developed by James Clark, suggests the possibility of a format style that is not merely descriptive, and approximates a true programming language. This track is followed by Netscape, which provides the W3C in 1996 to “JavaScript-Based Style Sheets (JSSS), implemented by Netscape Navigator 4 in 1997.

The origins of CSS are related to three major alternatives:

  • HTML is there a format or structure of a mixed format editing and structuring?
  • The choice of presentation of the author should they take precedence over those of the user?
  • The answer is she needs a format description of the formatting, or a transformation language?

The first developments

The first proposal for HTML Cascading Style Sheets made by Håkon Wium Lie holds the attention of Dave Raggett, who was then the chief editor of the draft specification HTML3.0. A supporter of a purely structural HTML, encourages publication of a paper CHSS, so that it can be presented and discussed at the Second International Conference on the WWW (Mosaic and the Web ‘, Chicago, 1994). It also modifies the browser with Håkon Lie Arena [14], to allow testing this format, and demonstrated at the Third Conference WWW 1995.

Meanwhile, Bert Bos, who was then working on the browser Argo, and who had submitted its own draft to the W3C “Stream-based Style Sheet Proposal (SSP), decides to join its effects to those of Håkon Lie. PHC was developed with the idea of being applicable not only HTML but also other markup languages, Bert Bos and Håkon Lie repeat this purpose, and form a key feature of the CSS itself becomes said.

Another aspect of CSS is so crucial to address the existing alternatives: CSS is the first format to include the idea of “cascading” (cascading style sheet), that is to say, the possibility for style a document to be inherited from more of a “style sheet”. This helps to mediate between several competing sources of shaping an element, and thus meets the need for compromise between the stylistic preferences of the authors and users.

The World Wide Web Consortium (W3C) becomes operational in 1995, and the mailing list www-style is created. The same year held in Paris a “W3C style sheet workshop” decisive for the future of CSS. Paper includes sets the goal to keep the style sheets in a simple form, which excludes the hypothesis JSSS Netscape. Moreover, Thomas Reardon (Microsoft), announcing the coming of CSS support in future versions of Internet Explorer, therefore, when the W3C creates the end of the “HTML Editorial Review Board (ERB HTML ) to ratify the future HTML specifications, DOM and CSS, Netscape, represented by Lou Montulli, finally joins the CSS project led by Bert Bos and Håkon Lie.

Towards a difficult maturation

Unlike software, the CSS specifications are developed by successive versions, which would allow a browser to refer to a specific version. CSS was developed by “levels”, which requires each new level to integrate the preceding, and each implementation to be compatible with its predecessor: CSS1 is developed to be a subset of CSS2, which is itself designed to be a subset of CSS3. This partly explains the slow progress normative CSS.

CSS1 implementations difficult during the browser wars

The CSS1 specification Final published December 17, 1996, and fifty sets of properties. CSS1 is defined as a mechanism of simple style sheet, allowing authors and readers to attach style in HTML documents. This simplicity is reflected in the choice of a language that can be easily read and written directly by human users, and language consistent with normal practice in publishing computer. The eventual choice to express CSS in XML or SGML syntax, regularly invoked to prevent the implementation of a new mode of parsing, is definitely ruled out.

CSS1 does not describe only its own grammar: the first level in fact describes a grammar to enable the later levels add new features, while authorizing the future reading these stylesheets by implementations of origin. These new features will not be included in the original implementations, but may be identified as such and ignored. CSS ensures its compatibility.

CSS1 defines essentially rendering properties Typographic text: fonts (fonts), color, font size, fat, spacing, border management and markers list. It is therefore no question of “layout” property float, which will be subsequently used heavily for CSS layout designs comprehensive web is then conceived as a way to place locally coast to coast, a small portion of content, such as a picture, and the rest of the text. Given the problematic implementations of CSS1, the diversion of the HTML table for managing the overall layout is immediately the most commonly used by the authors of web content.

In 1996, Internet Explorer 3.0 is the first commercial browser to implement CSS in part while it is still being formulated. This implementation early, led by Chris Wilson does not match the final specification. In 1997, Internet Explorer 4.0 saw the birth of a new rendering engine, Trident, causing the problem but growing support for CSS in different versions of the browser on Windows, until IE7 included.

Netscape Navigator 4.0 follows the movement in 1997, despite its historical reluctance vis-à-vis CSS in the context of the browser wars, then it is mainly to ensure that Microsoft can not emerge as the browser more compliant. However, this implementation precipitated, based on internal javascript methods, is finally revealing some readable content producers. Netscape Navigator 4.0 also provides an implementation JSSS, which will remain short-lived. Not until the new Gecko rendering engine and its integration in Netscape 6 for achieving real implementation of CSS1.

In 1998, while ending the browser wars between Netscape and Microsoft, Opera 3.5, which Håkon Lie has meanwhile become the technical director, achieves a more complete implementation of CSS1, facilitated by the publication of the first “Test Suite for Cascading Style Sheets (CSS) Level 1 “created mainly by Eric Meyer for the W3C [26]. The presence of these test suites is proving a major asset for both implementations in browsers and the appropriation of CSS techniques by the authors (by providing detailed examples of properties and their values).

Finally, under the leadership of Tantek Çelik, Internet Explorer 5.0 for Macintosh was launched in March 2000, based on the Tasman, a renderer specific unrelated Trident is the first browser to fully support (over 99%) CSS1. For compatibility with previous coding practices specific to each implementation (the “tag soup”) and allow the proper display of Web documents that are friendly or not standard CSS and HTML, it is also the first to implement the technique of doctype switching. Subsequently adopted by all browsers, it subsequently became one of the keys to the phased implementation of CSS: it makes it possible to keep old browser implementations owners for reasons of compatibility, while having the opportunity to opt, depending on the syntax of type declaration page document, a way to conform to new standards implementations.

During this period of the late 1990s, the web design is primarily dependent on the use of HTML as a presentation format. The defeat of Netscape after the browser wars, the renewal that follows through the Mozilla project, the appearance of IE5 Mac, and a lesser extent the evolution of Windows Internet Explorer 5.x , however, begin in the early 2000s a new stage in the evolution of design practices of the websites by the authors: These browsers make it possible to show that historical practice dating back to the browser wars, mixing structure and presentation, can really be abandoned in favor of an approach based on style sheets and more general respect for web standards (within the meaning of HTML and CSS). Jeffrey Zeldman, co-founder of the Web Standards Project and founder of A List apart in 1998, appears as the figurehead of this movement to promote standards. It is also the inspiration for a design approach “hybrid,” taking advantage of CSS techniques while residing temporarily in the context of formatting documents based on presentation boards.

Continued…

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