发个AJAX+JS实现的层拖动

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="MyTest.WebForm1" %><%@ Register Assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
    Namespace="System.Web.UI" TagPrefix="asp" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
    <script type="text/javascript" language="javascript">
    var move_obj_x0=0,move_obj_y0=0,move_obj_x1=0,move_obj_y1=0;//(x0,y0)为开始拖动时鼠标的位置(x1,y1)为开始拖动时对象的位置 
var obj_moveable=false; //开始拖动; 
function startDrag(obj,id) 
{ 
    if(event.button==1) 
    { 
        obj.setCapture(); 
        win=document.getElementById(id) 
        move_obj_x0 = event.clientX; 
        move_obj_y0 = event.clientY; 
        move_obj_x1 = parseInt(win.style.left); 
        move_obj_y1 = parseInt(win.style.top); 
        obj_moveable = true; 
    } 
} 
//拖动; 
function drag(id) 
{ 
    if(obj_moveable) 
    { 
        win=document.getElementById(id) 
        win.style.left = (move_obj_x1 + event.clientX - move_obj_x0>0)?move_obj_x1 + event.clientX - move_obj_x0:0; 
        win.style.top = (move_obj_y1 + event.clientY - move_obj_y0>0)?move_obj_y1 + event.clientY - move_obj_y0:0; 
    } 
} 
//停止拖动; 
function stopDrag(obj,id) 
{ 
    if(obj_moveable) 
    { 
        obj.releaseCapture(); 
        obj_moveable = false; 
    } 
}     </script>
</head>
<body>
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
    <div>
    <table cellSpacing="0" cellPadding="0" width="100%" border="0">
<tr>
<td height="25" width="30%" align="right">
TestID
</td>
<td height="25" width="*">
<asp:TextBox id="txtTestID" runat="server" Width="200px"></asp:TextBox>
</td></tr>
<tr>
<td height="25" width="30%" align="right">
TestName
</td>
<td height="25" width="*">
<asp:TextBox id="txtTestName" runat="server" Width="200px"></asp:TextBox>
</td></tr>
<tr>
<td height="25" width="30%" align="right">
TestDate
</td>
<td height="25" width="*">
        &nbsp;<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
        &nbsp;
        <asp:Button ID="Button2" runat="server" Text="Button" OnClick="Button2_Click" /></td></tr>
</table>
    </div>        <asp:UpdatePanel ID="UpdatePanel1" runat="server" Visible="False">
            <ContentTemplate>
            <div id="menu3"  style=" border:solid 1px;width:65%; z-index:5; position:absolute; left: 180px; top: 147px;"  runat="server"   onmousedown="startDrag(this,'menu3')" onmousemove="drag('menu3')" onmouseup="stopDrag(this,'menu3')">
                <asp:GridView ID="GridView1" runat="server">
                </asp:GridView>
            </div>
            </ContentTemplate>
        </asp:UpdatePanel>
    </form>
</body>
</html>