js 读取xml兼容各种浏览器

var xmlDom; //XML DOM object
var xmlFile="ff.xml"; //xml file name
loadXML = function(fileRoute){
xmlDoc=null;
if (window.ActiveXObject){
xmlDoc = new ActiveXObject('Msxml2.DOMDocument');
xmlDoc.async=false;
xmlDoc.load(fileRoute);
}else if (document.implementation && document.implementation.createDocument){
var xmlhttp = new window.XMLHttpRequest();
xmlhttp.open("GET",fileRoute,false);
xmlhttp.send(null);
var xmlDoc = xmlhttp.responseXML;
}
else {xmlDoc=null;}
return xmlDoc;
}
xmlDom=loadXML(xmlFile);
var newsList2=xmlDom.getElementsByTagName("item");
alert(newsList2.length)