兼容火狐、谷歌、IE等浏览器JS解析XML

/**
*加载XML
*/
window.onload=function()
{
    var oXmlHttp = null;
    var sUrl = "xxx.xml";
    //判断IE
if (window.ActiveXObject){
oXmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} 
//用于 Mozilla, Firefox, Opera, 等浏览器
else if (window.XMLHttpRequest){
oXmlHttp = new XMLHttpRequest();
}
if(oXmlHttp != null){  
oXmlHttp.open("GET",sUrl,false);
oXmlHttp.onreadystatechange=RequestCallBack;
oXmlHttp.send(null);
}
function RequestCallBack(){
if(oXmlHttp.readyState == 4){
if(oXmlHttp.status == 200){  //OK 状态获取XML字符串
var xmlObj=oXmlHttp.responseText;
var xmlObject = getXmlObj(xmlObj); //调用转换方法获取XML对象
alert("节点数组对象："+xmlObject.childNodes+" 节点个数"+xmlObject.childNodes.length);
}
}
}
}