firefox chrome ie9,10,11 不支持selectSingleNode和selectNodes的解决方法

firefox并不支持selectSingleNode和selectNodes的解决方法

function test(){
         var perid = document.thisForm.PerID.value;   

         var xml="test";
         if(window.ActiveXObject){
             var xml=new ActiveXObject("Microsoft.XMLDOM");
             xml.async=false;
             xml.load("xxxx.xml");   

         }else if((typeof document.implementation != 'undefined')&&
             (typeof document.implementation.createDocument!='undefined')){
             xml = document.implementation.createDocument("", "", null);   

             xml.async=false;
             xml.load("xxxx.xml");   

            //firefox并不支持selectSingleNode和selectNodes方法;下面两段是用XPath来解决firefox模拟selectSingleNode和selectNodes方法,正确性有待解决
             XMLDocument.prototype.selectSingleNode = Element.prototype.selectSingleNode = function (xpath){
                  var   x = this .selectNodes(xpath)
                 if ( ! x || x.length < 1 ) return   null ;
                 return   x[ 0 ];
             }
             XMLDocument.prototype.selectNodes = Element.prototype.selectNodes = function (xpath){
                  var   xpe   =   new   XPathEvaluator();
                  var   nsResolver   =   xpe.createNSResolver( this .ownerDocument   ==   null    ?
                     this .documentElement :  this .ownerDocument.documentElement);
                  var   result   =   xpe.evaluate(xpath,  this , nsResolver,  0 ,  null );
                  var   found   =   [];
                  var   res;
                 while   (res   =   result.iterateNext())
                     found.push(res);
                 return   found;
             }   

         }
        //下面就可以用selectSingleNode和selectNodes方法
         var row=null;   

        if(perid.substring(0,5)=="NO" &&　perid.length==9){
             row=xml.selectSingleNode("root/row[@ID='"+perid+"']");
            if (row!=null){
                 document.thisForm.MenuColor.value=row.getAttribute("CssFileName");
                 ChangeBgColor(document.thisForm.MenuColor.value);
             }
         }   

     }