Cascading Style Sheets | Part 3

Cascading Style Sheets | Part 3

CSS — Difficult to maturation

Unlike software, the CSS specifications are developed by successive versions, which would allow a browser to refer to a particular version. CSS was developed by “levels”, forcing each new level to integrate the preceding, and each implementation to be compatible with the previous one: 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 of normative CSS.

CSS1 implementations difficult during the browser wars

The final specification is published CSS1 December 17, 1996, and fifty sets of properties. CSS1 defines itself as a “mechanism simple style sheet, allowing authors and readers to attach style (etc.) in HTML documents. This simplicity is reflected in the choice of a language that can be easily read and written directly by its human users, and language consistent with normal practice in publishing computer. The eventual choice to express CSS syntax in XML or SGML, raised regularly 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 effect describes a grammar designed to allow the subsequent levels add new features, while authorizing the future reading these stylesheets by implementations of origin. These new features will not be understood by implementations of origin, but may be identified as such and ignored. CSS ensures its compatibility.

CSS1 essentially defines the typographical rendering properties of text: fonts (fonts), color, font size, fat, padding, border management and markers list. There is therefore no question of “layout” property float, which will be subsequently used extensively 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 an image, and the rest of the text. Given the problematic implementations of CSS1, the diversion of the HTML table for managing the overall layout remains the immediate solution 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 early implementation, 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 historic reticence vis–vis CSS : in the context of the browser wars, then it is mainly to ensure that Microsoft can not assert itself as the browser more compliant. However, this implementation precipitated, based on internal methods javascript, finally proves little 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 is H¥kon Lie meanwhile become the technical director, achieves a more complete implementation of CSS1, aided by the publication of the first “Test suite for Cascading Style Sheets (CSS) Level 1 “by Eric Meyer created primarily for the W3C. The presence of these test suites is proving a major asset for both implementations in browsers and ownership of CSS techniques by the authors (by providing detailed examples of properties and their values).

Finally, spurred on by Tantek lik, Internet Explorer 5.0 for Macintosh was launched in March 2000 based on Tasman, a specific renderer 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 to be respectful 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 in, according to the syntax of the type declaration page document, a method to conform to new standards implementations.

During this period the late 1990s, web design is primarily dependent on the use of HTML as a presentation format. Netscape’s defeat at the end of the browser wars, the renewal that follows through the Mozilla project, the appearance of IE5 Mac, and to a lesser extent the evolution of Windows Internet Explorer 5.x, however, begin in early 2000 a new stage in the evolution of design practices of the websites by the authors: These browsers make it possible to show that the historical practice dating back to the browser wars, mixing structure and presentation, can actually 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 staying temporarily in the context of formatting documents based on presentation boards.

CSS2, ambitions precipitated

To meet the first specification does not cover even CSS1, CSS is awarded in 1997 to a new working group within W3C, chaired by Chris Lilley. In 2007, this group included representatives from Apple, Google, IBM, Microsoft, Adobe, Mozilla Foundation and Opera.

Published as a recommendation in May 1998, the second level of CSS considerably extends the theoretical possibilities of cascading style sheets, especially with about 70 additional properties. At the typographic layout of text in addition CSS1 initiated with particular effect:

  • Declination in styles specific to different media in which a web page can be restored (print, delivered by a voice synthesizer, a Braille device, a projection device, a phone, etc.).
  • New positioning properties on the screen to enable the implementation of advanced layout, from a document developed jointly by Microsoft and Netscape
  • A set of properties allowing the downloading of fonts specific
  • New properties to involve the user preferences in the shaping of a site.

However, this rich functionality not found an echo in his limited implementations:

  • The breakdown by media is in part a failure: the vocal style renderings remain theoretical lack of consideration by voice browsers and screen readers. They are otherwise incompatible with the standard interaction SSML. It is the same display and printing Braille. Print styles are only very partially adopted by graphical browsers, while some mobile browsers do not yet know in the early 2000s the CSS media type that is dedicated to them.
  • Only a few advanced positioning properties are recognized by all graphical browsers, thus consolidating the practical layout based on deflections of CSS features (or floating block system set) and HTML (tables layouts).
  • The download fonts raises implementations and divergent between Netscape and Internet Explorer, and met opposition from publishers fonts, anxious to protect their commercial interests.

Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.

To be continued.


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