(function (window) {

    if (!window.jasen) {

        window.jasen = {};

    }

    if (!window.jasen.core) {

        window.jasen.core = {};

    }

    //------------------------------------------------

    // XML operation below.

    //------------------------------------------------

    if (!window.jasen.core.Xml) {

        window.jasen.core.Xml = {};

    }

    if (typeof jasen.core.Xml != "object") {

        throw new Error("Invalid entity jasen.core.Xml!");

    }

    function createXmlDocument() {

        //IE

        if (window.ActiveXObject) {

            return new ActiveXObject("Microsoft.XMLDOM");

        }

        //W3C

        else if (document.implementation && document.implementation.createDocument) {

            return document.implementation.createDocument('', '', null);

        }

        throw new Error("Xml is not supported by your brower!");

    }

    function loadXmlFile(xmlFile) {

        var xmlDocument = createXmlDocument();

        xmlDocument.async = false;

        xmlDocument.load(xmlFile);

        return xmlDocument;

    }

    function loadXmlText(xmlText) {

        // IE Must be tested first

        if (window.ActiveXObject) {

            var xmlDocument = new ActiveXObject("Microsoft.XMLDOM");

            xmlDocument.async = false;

            xmlDocument.loadXML(xmlText);

            return xmlDocument;

        }

        // W3C

        else if(window.DOMParser) {

            return (new DOMParser()).parseFromString(xmlText, "text/xml");

        }

        throw new Error("Xml is not supported by your brower!");

    }

    var Xml = window.Xml = window.jasen.core.Xml;

    Xml.createDocument = createXmlDocument;

    Xml.loadFile = loadXmlFile;

    Xml.loadText = loadXmlText;

})(window);

 <script language="javascript" type="text/javascript">

        function testXml() {

            var xmlDoc = Xml.loadFile("/Xml/House.xml");

            var xmlDocElement = xmlDoc.documentElement;

            var nodes = xmlDocElement.getElementsByTagName("city");

            var currNode = null;

            for (var i = 0; i < nodes.length; i++) {

                currNode = nodes[i]

            }

            var xmlText = "<address><city name='北京'><price>150万</price><type>一室三居</type></city></address>";

            xmlDocElement = Xml.loadText(xmlText);

            var cityName =  xmlDocElement.selectSingleNode("address/city/@name").nodeValue;

            var price = xmlDocElement.selectSingleNode("address/city/price/text()").nodeValue;

        }

    </script>