16.1.2 CSS History
CSS is a relatively old standard. CSS1 was adopted in December 1996 and defines properties for specifying colors, fonts, margins, borders, and other basic styles. Browsers as old as Netscape 4 and Internet Explorer 4 include substantial support for CSS1. The second edition of the standard, CSS2, was adopted in May 1998; it defines a number of more advanced features, most notably support for absolute positioning of elements. CSS2.1 clarifies and corrects CSS2, and it removes features that browser vendors never actually implemented. Current browsers have essentially complete support for CSS2.1, although versions of IE prior to IE8 have notable omissions.
Work continues on CSS. For version 3, the CSS specification has been broken into various specialized modules that are going through the standardization process separately. You can find the CSS specifications and working drafts at http://www.w3.org/ Style/CSS/current-work .欢迎转载,转载请注明来自一手册:http://yishouce.com/book/1/31441.html