var xhrObj=getXHRObject();
xhrObj.onreadystatechange=
function(){
if(xhrObj.readyState==4){
var scriptElem=document.createElement(‘script‘);
document.getElementsByTagName(‘head‘)[0].appendChild(ScriptElem);
scriptElem.text=xhrObj.responseText;
}
};
xhrObj.open(‘Get‘,‘A.js‘,true);//必须和主页面在同一个域中
xhrObj.send(‘‘);