have got succesfull done it in the content pages, but in the masterpage, I am not able to done it. I tried this way, it was like I did for content pages.

<script type="text/javascript">
    // This Script is used to maintain Grid Scroll on Partial Postback
    var scrollTop;
    //Register Begin Request and End Request 
    Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
    Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
    //Get The Div Scroll Position
    function BeginRequestHandler(sender, args) 
    {
        var m = document.getElementById('<%=PanelMenuLeft.ClientID%>');                                                                    
        m.scrollTop = scrollTop;

    }
    //Set The Div Scroll Position
    function EndRequestHandler(sender, args)
    {
        var m = document.getElementById('<%=PanelMenuLeft.ClientID%>');
        m.scrollTop = scrollTop;
    } 
</script>