不刷新dropdownlist聯動

js:

<script type="text/javascript">
//<![CDATA[
    function fLoadXml(url, show){
    var drp1 = document.getElementById("DropDownList1");
    var ClassID=drp1.options[drp1.selectedIndex].value;
    
    var oHttpReq = new ActiveXObject("MSXML2.XMLHTTP");
　　var oDoc = new ActiveXObject("microsoft.xmldom");
　　oHttpReq.open("POST", "no_refresh2.aspx?ClassID="+ClassID, false); 
　　//
　　//调用读取小类数据的页面，将大类
　　// 编号值传递过去
　　oHttpReq.send("");
　　//result = oHttpReq.responseText;
　　
        switch(fCkDom2()){
            case 1:
                var xml=document.implementation.createDocument('','',null);
                    xml.onload = function(){show(xml, url);}
                    xml.load(url);
                break;
            case 2: 
                var xml=new ActiveXObject('microsoft.xmldom');
                    xml.onreadystatechange=function(){
                        if(xml.readyState==4){
                            show(xml, url);
                        }
                    } 
                    xml.load(url);
                break;
            default: document.write('unknown');
        }
        
        function fCkDom2(){
            if(document.implementation&&document.implementation.createDocument)return 1;
            else if(window.ActiveXObject) return 2;
            else return 0;
        }
    }
    
    function fShowXml(xml, url){
    var drp2 = document.getElementById("DropDownList2");
    //alert(drp2);
　 function RemoveAll(oElem) { //清除DropDownList2的所有项
　　var i = 0;
　　for (i = oElem.length; i >= 0; i--){
　　oElem.options.remove(i);
　　}
　　}
　　RemoveAll(drp2);
　　//将小类的类名和编号赋予DropDownList2
//alert(content);
    var tOption = document.createElement("OPTION");
    tOption.text="請選擇";
    //　alert(newOption.text);
    tOption.value="請選擇";
   //alert(newOption.value);
   drp2.options.add(tOption);
　　
        //alert('ok');
        var elements=xml.getElementsByTagName('Table');
            for(var i=0; i<elements.length; i++){
                
                for(var j=0; j<elements[i].childNodes.length; j++){
                    if(elements[i].childNodes[j].nodeType==1){
                        var eSub=elements[i].childNodes[j]
                    
                        var content;
            
                            try{
                                content=eSub.firstChild.data;//.fontcolor('blue');
                            } catch(e){
                                content='empty';
                            }
                    
                    //将小类的类名和编号赋予DropDownList2
                    //alert(content);
                    　var newOption = document.createElement("OPTION");
                    　　newOption.text=content;
                    　//　alert(newOption.text);
                    　　newOption.value=content;
                    　　//alert(newOption.value);
                    　　drp2.options.add(newOption);
                    }
                }  
            }
    }
//]]>onload="fLoadXml('xml.xml', fShowXml);"onload="fLoadXml('xml.xml', fShowXml);"
</script>

主頁code:
 Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
   If Not Page.IsPostBack Then
            Dim myda As System.Data.SqlClient.SqlDataAdapter
            Dim ds As System.Data.DataSet
  sqlcomm("goods_tree")'調用存儲過程
            Dropdownlist_Bind(Me.DropDownList1, mycomm, "0", "2")‘綁定
            '"javascript:document.Form1.TH.value=this.options[this.selectedIndex].value;");
            Me.DropDownList1.Attributes.Add("onchange", "fLoadXml('xml.xml', fShowXml);")’調用事件
  End If

調用數據html:
Imports System.Xml
Imports System.IO

 Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim myda As System.Data.SqlClient.SqlDataAdapter
        Dim ds As System.Data.DataSet
        ' Request.QueryString("ClassID") = "2"
        If (Me.Request.QueryString("ClassID") <> Nothing) Then
            Dim state As String = Me.Request.QueryString("ClassID").ToString()
            Try
                '綁定市

                sqlcomm("goods_select_code")
                ' SELECT distinct CountryRegion,StateProvince
                'from Geography
                With mycomm
                    .Parameters.AddWithValue("@Goods_ID", state.Trim) 'state.Trim
                End With
                myda = New System.Data.SqlClient.SqlDataAdapter(mycomm)
                ds = New Data.DataSet("pro")
                ds.Tables.Clear()
                sqlconn_Open()
                myda.Fill(ds)
                sqlconn_Close()
                '   ds.WriteXml("xml.xml", XmlWriteMode.WriteSchema)
                ds.WriteXml(Server.MapPath("xml.xml"))
            Catch ex As Exception

            End Try

        End If

    End Sub