PUBLIC MARKS from Hiéroglyphe with tag browser

This is the second in a series of articles describing experiments conducted to learn more about optimizing web page performance. You may be wondering why you’re reading a performance article on the YUI Blog. It turns out that most of web page performance is affected by front-end engineering, that is, the user interface design and development.

In order to deal with both old tag soup written to old browser quirks and new CSS-compliant pages, Firefox (and other Mozilla Gecko-based browsers), Safari, Opera (7 and later), Internet Explorer 6 and 7, Mac IE 5, and Konqueror (3.2 and later) have two main layout modes. In one mode the layout engine attempts to render conforming pages according the CSS specifications. In the other mode the layout engine tries to mimic old browsers. In Firefox these modes are known as “the Standards mode” and “the Quirks mode” respectively. In this document the same names are used also when referring to the modes of the other browsers.

This document will summarize the level of support for web standards and maturing technologies in popular web browsers. It covers the Internet Explorer, Firefox, and Opera web browsers, with focus on the HTML, CSS, DOM, and ECMAScript technologies.

These charts compare basic support for the various selectors, pseudo-classes and pseudo-elements defined in the CSS Selectors module