Presentation Layer

Now that all presentation instructions have been removed from the markup standard, this information is the exclusive job of Cascading Style Sheets. Style sheets standards are being developed in phases, as follows.

Cascading Style Sheets (CSS) Level 1

This style sheet standard has been a Recommendation since 1996 and is now fully supported by current browser versions. Level 1 contains rules that control the display of text, margins, and borders.

CSS Level 2.1

This Recommendation is best known for the addition of absolute positioning of web page elements. Level 2 reached Recommendation status in 1998, and the 2.1 revision is a Candidate Recommendation as of this writing. Support for CSS 2.1 is still inconsistent in current browser versions.

CSS Level 3

Level 3 builds on Level 2 but is modularized to make future expansion simpler and to allow devices to support logical subsets. This version is still in development.

You can find links to all three CSS specifications on this page: http://www.w3.org/Style/CSS. Style sheets are discussed further in Part III in this book.

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