Javascript文件的动态下载
function loadScript(url,callback){ var script=document.createElement("script"); script.type="text/javascript"; if(script.readyState){ script.onreadystatechange=function(){ if(script.readyState=="loaded" || script.readyState=="complete"){ script.onreadystatechange=null; callback(); }; } }else{ script.onload=function(){ callback(); }; }; script.src=url; document.getElementsByTagName("head")[0].appendChild(script); };