Here are simple 3 steps -
Step 1: Write all javascript or jQuery code inside a function like following-
<script>
function BindIt()
{
alert("execute again");
//****Add your code here***//
----
-----
}
</script>
Step 2: Call "BindIt()" function on Body onload event.
<body onload="javascript:BindIt()">
Step 3: Add following javascript code inside UpdatePanel..and All Done..
<form runat="server" ID="form1">
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<script type="text/javascript">
Sys.Application.add_load(BindIt);
</script>