【转】js动态加载脚本

以下代码转自cssrain http://www.cssrain.cn/?p=1421
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 <html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <title></title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <body>

 <script>
 function loadScript(url, callback){
    var script = document.createElement("script")
    script.type = "text/javascript";
    if (script.readyState){  //IE
        script.onreadystatechange = function(){
            if (script.readyState == "loaded" ||
                    script.readyState == "complete"){
                script.onreadystatechange = null;
                callback();
            }
        };
    } else {  //Others
        script.onload = function(){
            callback();
        };
    }
    script.src = url;
    document.getElementsByTagName("head")[0].appendChild(script);
}
</script>

<script type="text/javascript">
loadScript("http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js", function(){
	alert('load success1!');
});
</script>

 </body>
 </html>