求助！使用JS脚本，以SAX2方式解析XML文件？

SAX?刚才写了一个简单的例子(JavaScript):
    var wrt   = new ActiveXObject("Msxml2.MXXMLWriter");
    var rdr   = new ActiveXObject("Msxml2.SAXXMLReader");    wrt.byteOrderMark = 1;
    wrt.omitXMLDeclaration = 0;
    wrt.indent = 1;

    rdr.contentHandler = wrt;
    rdr.dtdHandler = wrt;
    rdr.errorHandler = wrt;    rdr.parseURL("http://www.csdn.net/Menu/Develop_xml.xml");
    alert(wrt.output);