function ShowTab(sender, tabContentToShow)
{

    var tabbedDivs = $$('div#mainTabbedContent div.tabContent');
    // hide all content
    for (i=0; i<tabbedDivs.length; i++)
    {
        tabbedDivs[i].style.display = 'none';
    }
    
    // set all tabs to unselected
    var selectedTabs = $$('div#mainTabbedContent a.selectedTab');
    for (i=0; i<selectedTabs.length; i++)
    {
        selectedTabs[i].className = 'unselectedTab';
    }
    
    // select the tab and show it's content
    $(tabContentToShow).style.display = 'block';    
    sender.className = 'selectedTab';
}

// show this tab when the DOM has loaded
Event.onDOMReady(   function() 
                    { 
                        ShowTab($('tabNav1'), $('tabContent1'));  
                    }
                 );