Updatepanel jquery 失效解决方案

<%@ Page Title="About Us" Language="vb" MasterPageFile="~/Site.Master" AutoEventWireup="false"
CodeBehind="About.aspx.vb" Inherits="JavaScriptSample.About" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
<script type="text/javascript" src="../Scripts/jquery-1.4.1.min.js"></script>
<script type="text/javascript">
$(function() {
BindEvents();
});
　　　　function BindEvents() {

　　　　　　$(":checkbox:first").bind('click', function () {
if (this.checked == true) {
$(":checkbox:gt(0)").attr('checked', 'true');
} else {
$(":checkbox:gt(0)").removeAttr("checked")
}
});

$(":checkbox:gt(0)").bind('click', function () {
var checkedCounter = 0;
$(":checkbox:gt(0)").each(function () {
if (this.checked == true) {
checkedCounter++;
}
});

if (checkedCounter == 4) {
$(":checkbox:first").attr('checked', 'true');
} else {
$(":checkbox:first").removeAttr("checked")
}
});

　　　　}
</script>
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<script type="text/jscript" >
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_endRequest(function () {
// re-bind your jquery events here
BindEvents();
});
</script>
<asp:CheckBox ID="cbAll" runat="server" Text="cbAll" />
<asp:CheckBox ID="CheckBox1" runat="server" Text="cb1" />
<asp:CheckBox ID="CheckBox2" runat="server" Text="cb2" />
<asp:CheckBox ID="CheckBox3" runat="server" Text="cb3" />
<asp:CheckBox ID="CheckBox4" runat="server" Text="cb4" />
<asp:Button runat="server" ID="btn1" Text="Text" />
</ContentTemplate>
</asp:UpdatePanel>
</asp:Content>