js解析xml浏览器兼容性处理

 /******************************************************************************
     说明：xml解析类
 ******************************************************************************/

 function XMLDOCDocument() {
     this.xmlDoc = null;
     this.async = false;
     this.xml = null;
 };

 function createDocument() {
     if (typeof arguments.callee.activeXString != "string") {
         var versions = ["MSXML2.DOMDocument.6.0", "MSXML2.DOMDocument.3.0", "MSXML2.DOMDocument"],
         i, len;
         for (i = 0, len = versions.length; i < len; i++) {
             try {
                 new ActiveXObject(versions[i]);
                 arguments.callee.activeXString = versions[i];
                 ActiveXObject(arguments.callee.activeXString);
                 break;
             } catch (ex) {
                 //跳过
             }
         }
     }
     return new ActiveXObject(arguments.callee.activeXString);
 };
 /*
 描述：加载xml
 */
 XMLDOCDocument.prototype.loadXML = function (xmlInfo) {
     //判断浏览器的类型
     //支持IE浏览器

     var isLoad = false;
     var xmlDomVersions = ['MSXML.2.DOMDocument.6.0', 'MSXML.2.DOMDocument.3.0', 'Microsoft.XMLDOM'];
     for (var i = 0; i < xmlDomVersions.length; i++) {
         try {
             this.xmlDoc = new ActiveXObject(xmlDomVersions[i]);
             this.xmlDoc.async = this.async;
             this.xmlDoc.loadXML(xmlInfo); //loadXML方法载入xml字符串
             this.xml = this.xmlDoc.documentElement.outerHTML;
             isLoad = true;
             break;
         } catch (e) {
         }
     }
     if (!isLoad) {
         if (typeof DOMParser != "undefined") {
             this.xmlDoc = (new DOMParser()).parseFromString(xmlInfo, "text/xml");
             this.xml = this.xmlDoc.documentElement.outerHTML;
             var errors = this.xmlDoc.getElementsByTagName("parsererror");
             if (errors.length) {
                 throw new Error("XML parsing error:" + errors[0].textContent);
             }
         } else {
             throw new Error("No XML parser available.");
         }
     }
 };

 /*
 说明：选择所有符合条件的节点
 */
 XMLDOCDocument.prototype.selectNodes = function (xPath) {
     return this.xmlDoc.selectNodes(xPath);
 };
 /*
 说明：选择一个符合条件的节点
 */
 XMLDOCDocument.prototype.selectSingleNode = function (xPath) {
     return this.xmlDoc.selectSingleNode(xPath);
 };

 /*
 说明：创建新节点
 */
 XMLDOCDocument.prototype.createElement = function (nodeName) {
     return this.xmlDoc.createElement(nodeName);
 };

 /*
 说明：创建新属性
 */
 XMLDOCDocument.prototype.createAttribute = function (attrName) {
     return this.xmlDoc.createAttribute(attrName);
 };
 /*
 说明：获得xml字符串
 */
 XMLDOCDocument.prototype.getXml = function () {
     //return this.xmlDoc.xml;
     if (typeof this.xmlDoc.xml != "undefined") {

         return this.xmlDoc.xml;
     }
     else if (typeof XMLSerializer != "undefined") {
         return (new XMLSerializer()).serializeToString(this.xmlDoc);
     } else {
         throw new Error("Could not serialize XML DOM.");
     }
 };
 /*
 说明：获得xml字符串
 */
 XMLDOCDocument.prototype.toString = function () {
     //return this.xmlDoc.xml;
     if (typeof this.xmlDoc.xml != "undefined") {

         return this.xmlDoc.xml;
     }
     else if (typeof XMLSerializer != "undefined") {
         return (new XMLSerializer()).serializeToString(this.xmlDoc);
     } else {
         throw new Error("Could not serialize XML DOM.");
     }
 };

 // check for XPath implementation
 if (document.implementation.hasFeature("XPath", "3.0")) {
     // prototying the XMLDocument
     XMLDocument.prototype.selectNodes = function (cXPathString, xNode) {
         if (!xNode) {
             xNode = this;
         }
         var oNSResolver = this.createNSResolver(this.documentElement)
         var aItems = this.evaluate(cXPathString, xNode, oNSResolver, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null)
         var aResult = [];
         for (var i = 0; i < aItems.snapshotLength; i++) {
             aResult[i] = aItems.snapshotItem(i);
         }
         return aResult;
     };

     // prototying the Element
     Element.prototype.selectNodes = function (cXPathString) {
         if (this.ownerDocument.selectNodes) {
             return this.ownerDocument.selectNodes(cXPathString, this);
         }
         else {
             throw "For XML Elements Only";
         }
     };

     // prototying the XMLDocument
     XMLDocument.prototype.selectSingleNode = function (cXPathString, xNode) {
         if (!xNode) { xNode = this; }
         var xItems = this.selectNodes(cXPathString, xNode);
         if (xItems.length > 0) {
             return xItems[0];
         }
         else {
             return null;
         }
     };

     // prototying the Element
     Element.prototype.selectSingleNode = function (cXPathString) {
         if (this.ownerDocument.selectSingleNode) {
             return this.ownerDocument.selectSingleNode(cXPathString, this);
         }
         else { throw "For XML Elements Only"; }
     }

     Element.prototype.__defineGetter__("innerText",
         function () {
             return this.textContent;
         }
     );

     Element.prototype.__defineSetter__("innerText",
         function (sText) {
             this.textContent = sText;
         }
     );

 };