Web Development

The evolution of style sheets

Here's some information about the evolution of style sheet, particularly CSS.

By Matt Rotter, Charity Kahn, and Paul Anderson

The Web has come a long way from its all-text beginnings. At first, we were happy just to be able to use images and wrap text around them. But tables, frames, and new cosmetic HTML tags came into use as appearance became more important on the rapidly growing Web. The principal browser vendors, Netscape and Microsoft, competed by adding support for new, proprietary tags and technologies that permitted increasingly high-impact Web pages.

These innovations were good for spurring the development of Web technology, but they created problems as well. It became more difficult to make Web pages compatible with all browsers, and developers were using HTML less to define content structure and more as an inefficient presentation system. To solve these issues, developers and the browser makers turned to the World Wide Web Consortium (W3C), the standards body responsible for HTML specifications.

The W3C was already developing a counterpart language for appearance and layout. This language was called Cascading Style Sheets, or CSS, and the W3C released its first specification in December 1996. Unlike HTML, CSS is designed solely to define appearance as efficiently as possible. And it can exist either within HTML or as a linked document, letting developers separate a Web page's content (marked up in HTML) from its presentation (defined by CSS.) This clear separation enables further advances such as internationalization, improved accessibility, and the Document Object Model (DOM) for manipulating a page's contents or appearance via script.

Browser support for the CSS standard has come rather slowly, beginning with the 4.0 releases of Navigator and Internet Explorer in late 1997, and as a result, CSS has yet to be widely adopted. However, browsers that don't support CSS can still access a Web page's content even if they don't see its intended presentation. Given the strong CSS support in Internet Explorer, Opera, and the upcoming Netscape 6, the Web is certainly ready for style sheets.

Matt Rotter and Charity Kahn are software engineers for CNET.com.

Paul Anderson is an associate technical editor for CNET Builder.com.