ajax的问题

[NightMouse_Space]

function OnEvent(id, Event, p1, p2, p3, p4){
		if(Event=="Clicked"){
			if(p3=="clk")
			{
				 AF.func("Calc", "");
			}else if(p3=="url"){
				var name=AF.func("GetCellData",p1+"\r\n"+p2);
				name=encodeURIComponent(name);
			//	alert(name);
				var xmls;
				if(window.XMLHttpRequest){
					xml=new XMLHttpRequest();
					if(xml.overrideMimetype){
						xml.xml.overrideMimetype("text/xml");
					}
				}else if (window.ActiveXObject){
					 var MSXML = ['MSXML2.XMLHTTP.6.0', 'MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0','MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP', 'Microsoft.XMLHTTP'];
					for(var i=0;i<MSXML.length;i++){  
					   try{  
							xml=new ActiveXObject(MSXML[i]);  
							break;
						}catch(e){}
					}
				}
				if(xml==undefined || xml==null){
					resultNode.innerHTML = "不能建立XMLHttpRequest对象";
					alert("XMLHttpRequest对象创建失败！！");
				}
				
				xml.open("GET","ajax.aspx?name="+name+"&type=gotoUrl",true);
				xml.send(null);
				xml.onreadystatechange = function () {
				    if (xml.readyState == 4) {
				        if (xml.status == 200) {
				            alert("获取到");
				            //resultNode.innerHTML=xml.responseText;
				            var tmp=xml.responseText;
				            alert(tmp);
				        } else {
				            alert("server error");
				        }
				    }
				};
			}
			//f
		}
	}

服务端页面

  if ((this.Session["UserName"] == null) || (this.Session["UserName"].ToString().Trim() == ""))
        {
           Response.Write("请先登录在访问本页面.");
            return;
        }
       // return;
	string sUserName = this.Session["UserName"].ToString().Trim();
        SqlConnection conn = new SqlConnection("Server=192.168.0.10;Database=MYWT_MIS_SGXM_BI_GUANLI;uid=mywtadmin;pwd=admin");
        SqlCommand cmd = new SqlCommand();
        try
        {
            conn.Open();
        }
        catch (Exception)
        {
            Response.Write("数据库链接失败!");
            conn.Close();
            throw;
        }
        string sName = Request["name"];
		string sType = Request["type"];
        string sTmp = "";
		switch(sType){
			case "gotourl":
                SqlDataAdapter dbAdapter = null;
                DataSet ds = null;
                DataTable objDt = null;
                cmd.CommandText = "SELECT myID FROM mywt_mis_SGXM_GC_GuanLi.dbo.单位工程开工报告 where 工程名称 like '%"+sName+"%';";
                cmd.Connection = conn;
                dbAdapter = new SqlDataAdapter(cmd);
                ds = new DataSet();
                dbAdapter.Fill(ds);
                objDt = ds.Tables[0];
                if (objDt != null && objDt.Rows.Count > 0){
                    for (int i = 0; i < objDt.Rows.Count; i++){
                        for (int j = 0; j < objDt.Columns.Count; j++){
                           sTmp = objDt.Rows[i][j].ToString().Trim();
                        }
                    }
                   // sTmp = this.CreateJsonParameters(objDt);
                    Response.Write(sTmp);
                    
                }
                cmd = null;
                dbAdapter = null;
                ds = null;
                objDt = null;
                conn.Close();
				
				//Response.End();
                break;
            default:
cmd = null;
                dbAdapter = null;
                ds = null;
                objDt = null;
                conn.Close();
                return;
        }

服务端页面有返回的字符串是个ID的值.为什么xml.responseText总是空...用的IE浏览器