js问题

[石头飘北]

function loadDataNew (parentid,dataAction,dataUrl,columnArr,orgid,orgString)
{
var xml = new ActiveXObject("Microsoft.XMLDOM")
xml.async = false
xmlUrl=this.dataUrl+"?action="+this.dataAction+"&parentid=";
var url = xmlUrl + this.parentid+"&orgid="+orgid;
xml.load(url);
xml.setProperty("SelectionLanguage", "XPath");
alert(xml.parseError.errorCode) ;
if (xml.parseError.errorCode != 0) {
var myErr = xml.parseError;
document.write("You have error " + xml.reason);
}else
{
return createTableNode(xml);
}
}

为什么 我 alert(xml.parseError.errorCode) 不是 0 呢?