Slow performance of a GridView inside an UpdatePanel

Here is an interesting problem we ran into recently.  The customer had a large GridView that was being updated by AJAX inside on UpdatePanel and seeing bad performance.
The reason is that the Client-Side Javascript has to walk the entire DOM of the Content of the UpdatePanel to tear down the HTML DOM as the Page goes through an Asynchronous update.
First Solution To alleviate the Expensive Stack Walks to destroy DOM Elements and its related Time Delay, the developers suggested that we remove the Unnecessary payload from the DOM of the UpdatePanel during an Asynch Postback.
The Way you would implement this is to:
1. Hook up an Event handler to the beginRequest Event .
EX:
<script language ="javascript" type ="text/javascript">
  Sys.WebForms.PageRequestManager.getInstance().add_BeginRequest(clearDisposableItems)
</script>

2. Destroy an DOM Elements th ...