Каскадные таблицы стилей, уровень 1.Спецификация CSS1


Appendix E: The applicability and extensibility of CSS1


(This appendix is informative, not normative)

The goal of the work on CSS1 has been to create a simple style sheet mechanism for HTML documents. The current specification is a balance between the simplicity needed to realize style sheets on the web, and pressure from authors for richer visual control. CSS1 offers:

  • visual markup replacement: HTML extensions, e.g. "CENTER", "FONT" and "SPACER", are easily replaced with CSS1 style sheets.

  • nicer markup: instead of using "FONT" elements to achieve the popular small-caps style, one declaration in the style sheet is sufficient. Compare the visual markup:

    <H1>H<FONT SIZE=-1>EADLINE</FONT></H1>

with the style sheet:

H1 { font-style: small-caps }

<H1>Headline</H1>

  • various integration levels: CSS1 style rules can be fetched from external style sheets, included in the 'STYLE' element, or put into 'STYLE' attributes. The latter option offers easy transition from HTML extensions.

  • new effects: some new visual effects have been added to offer users new toys. The typographical pseudo-elements and the extra values on the background property fall into this category.

  • scalability: CSS1 will be useful on equipment ranging from text terminals to high-resolution color workstations. Authors can write one style sheet and be reasonably sure that the intended style will come across in the best possible manner.

  • CSS1 does not offer:

    • per pixel control: CSS1 values simplicity over level of control, and although the combination of background images and styled HTML is powerful, control to the pixel level is not possible.

    • author control: the author cannot enforce the use of a certain sheet, only suggest

    • a layout language: CSS1 does not offer multiple columns with text-flow, overlapping frames etc.

    • a rich query language on the parse tree: CSS1 can only look for ancestor elements in the parse tree, while other style sheet languages (e.g. DSSSL [6]) offers a full query language.




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