ASP.NET AJAX not working on Google Chrome and Safari - Update panel/Popup Extender.

Issue:
Recently i faced this issue when working with ASP.NET Ajax Updatepanel and Popup extender. The Popup was always visible and took a fixed space on the page like a normal div.

Solution:
Added the below javascript code to a .js file.
Sys.Browser.WebKit = {}; //Safari 3 is considered WebKit
if( navigator.userAgent.indexOf( 'WebKit/' ) > -1 )
{
  Sys.Browser.agent = Sys.Browser.WebKit;
  Sys.Browser.version = parseFloat( navigator.userAgent.match(/WebKit\/(\d+(\.\d+)?)/)[1]);
  Sys.Browser.name = 'WebKit';
}

Refer the .js file in the ScriptManager.
<ajax:ToolkitScriptManager ID="scripts" runat="server" ScriptMode="Release" EnableHistory="true"
EnableSecureHistoryState="false" EnablePageMethods="True" CombineScripts="true"
OnAsyncPostBackError="Page_OnAsyncError" OnNavigate="OnHistoryNavigate">
    <Scripts>
        <asp:ScriptReference Path="~/js/webkit.js" />
    </Scripts>
</ajax:ToolkitScriptManager>