function Change_Select()
        {
            var zhi=document.getElementById('省ID号').value;
            var url="解析地址&id="+escape(zhi);
            if(window.XMLHttpRequest)
            {
                req=new XMLHttpRequest();
            }else if(window.ActiveXObject)
            {
                req=new ActiveXObject("Microsoft.XMLHTTP");
            }
            
            if(req)
            {
                req.open("GET",url,true);
                req.onreadystatechange=callback;
                req.send(null);
            }
        }
        
        function callback()
        {
            if(req.readyState == 4)
            {
                if(req.status == 200)
                {
                    parseMessage();
                }else{
                    //alert("不存在对应值");
                }
            }
        }
        
        function parseMessage()
        {
            var xmlDoc=req.responseXML.documentElement;
           // alert(xmlDoc);
            var xSel=xmlDoc.getElementsByTagName('select');
            var select_root=document.getElementById('市id号');
            select_root.options.length=0;
            for(var i=0;i<xSel.length;i++)
            {
                var xValue=xSel[i].childNodes[0].firstChild.nodeValue;
                var xText=xSel[i].childNodes[1].firstChild.nodeValue;
                var option=new Option(xText,xValue);
                try{
                    select_root.add(option);
                }catch(e){
                }
            }
        }