Utilisez ce code pour ajouter des règles CSS dynamiquement (testé sur la majorité des navigateurs) :
function dyn_css_rule(sSelector, sCssText) {
try {
var aSS = document.styleSheets;
var i;
for (i=aSS.length-1; i>=0; i--) {
var oCss = document.styleSheets[i];
var sMedia = (typeof(oCss.media) == "string")?
oCss.media:
oCss.media.mediaText;
if (!sMedia
|| sMedia.indexOf("screen") != -1
|| sMedia.indexOf("all") != -1
) {
break;
}
}
if (oCss.insertRule) {
oCss.insertRule(sSelector + " {" + sCssText + "}", oCss.cssRules.length);
} else if (oCss.addRule) {
oCss.addRule(sSelector, sCssText);
}
} catch(err) {
var tag = document.createElement('style');
tag.type = 'text/css';
try {
tag.innerHTML = sSelector + " {" + sCssText + "}";
} catch(err) {
tag.innerText = sSelector + " {" + sCssText + "}";
}
document.getElementsByTagName('head')[0].appendChild(tag);
}
return sSelector + "{" + sCssText + "}";
};
Utilisation :
dyn_css_rule("h1", "color: #F00");