javascript实现动态加载CSS

<script type="text/javascript">
            function addStyle(stylePath) {
                var container = document.getElementsByTagName("head")[0];
                var addStyle = document.createElement("link");
                addStyle.rel = "stylesheet";
                addStyle.type = "text/css";
                addStyle.media = "screen";
                addStyle.href = stylePath;
                container.appendChild(addStyle);
            }
            addStyle('http://www.xxx.com/wintys/dynamic.css');
</script>

function $import(path,type,title){
var s,i;
if(!type) type=path.substr(path.lastIndexOf(".")+1);
if(type=="js"){
    var ss=document.getElementsByTagName("script");
    for(i=0;i<ss.length;i++){
        if(ss[i].src && ss[i].src.indexOf(path)!=-1 || ss[i].title==title)return ss[i];
    }
    s=document.createElement("script");
    s.type="text/javascript";
    s.src=path;
    if(title) s.title=title;
}
else if(type=="css"){
    var ls=document.getElementsByTagName("link");
    for(i=0;i<ls.length;i++){
        if(ls[i].href && ls[i].href.indexOf(path)!=-1 || ls[i].title==title)return ls[i];
    }
    s=document.createElement("link");
    s.rel="stylesheet";
    s.type="text/css";
    s.href=path;
    if(title) s.title=title;
    s.disabled=false;
}
else return;
var head=document.getElementsByTagName("head")[0];
head.appendChild(s);
return s;
}