js为元素动态添加css代码

 IE：

cssStr = "p { color:#FF0000;} a { font-size:9pt;}";
var style = win.document.createStyleSheet();
style.cssText = cssStr;

FF：

cssStr = "p { color:#FF0000;} a { font-size:9pt;}";
var style = win.document.createElement("style"); 
style.type = "text/css"; 
style.innerHTML = cssStr; 
win.document.getElementsByTagName("HEAD").item(0).appendChild(style);