alistapart.com/stories/alternate/ for more information). Any style sheet lacking a title attribute (and a rel value of stylesheet) is persistent??”always affecting a document. These are by far the most common types of style sheets. A preferred style sheet also takes a title along with the rel attribute and only one such style sheet can be used at a time??”typically the first, with subsequent ones ignored. On pages that offer alternate style sheets (typically via a style switcher), the persistent styles are always used, and the first preferred is the additional default; the preferred styles, however, can be swapped out by selecting an alternative style sheet. (Note that in Firefox, you should avoid adding a title attribute to any style sheet for print, because otherwise the content may not print.) In the previous example, the media attribute is set to all, specifying that this style sheet is intended for all devices. But it??™s feasible to attach multiple style sheets to a web page, and set the media attribute of each one to a different type. For instance, in the following example, two CSS files are attached, one for screen and the other for printed output: ?? media="screen" /> ?? media="print" /> There are other media types, including aural, braille, projection, and tv, but few are supported well. However, in Chapter 10, we??™ll look at style sheets for print, which is one of the alternatives to screen that is supported reasonably well in mainstream browsers.