<style> with negated mediaThis text will be green if the rule has been applied.
<style type="text/css" media="not all">
/*<![CDATA[*/
#testElement {
color: #00ff00;
}
/*]]>*/
</style>
Because all media types belong to the all family, specifying a media of not all should insure that the stylesheet should never be imported. Standards-compliant browsers will not apply this rule (so the text in the example block should be red in compliant browsers).