AJAX :: Change A 2nd Level Tabcontainer ActiveTabIndex When The Page Is Being Loaded?

I'm using C#, asp.net and ajaxtoolkit

I want to set up menu item links such that the tab index is sent in the query string parameter. I tried setting the ActiveTabIndex in the Page_Load event and that doesn't change it at all. I tried using the javascript and I think because this tabcontainer is contained in a UpdatePanel's ContentTemplate so that javascript is not able to find it? How can I do this?

<script type="text/javascript">
// function SetInitalTabChanged() {
// var leaderTabs = $get('<%=TabLeadershipMain.ClientID%>');
// leaderTabs = leaderTabs.control; //
// leaderTabs.set_activeTabIndex(0);
// }
function SetInitalTabChanged() {
// $('<%=TabLeadershipMain.ClientID%>').set_activeTabIndex(0);
var container = $find('TabLeadershipMain');
container.set_activeTabIndex(0);
}

With javascript above (both) I would get the error below

Microsot runtime jscript error:Object doesn't support this property or method

Or if use the commented out function it will return leaderTabs = null