function init()
{
    Event.observe($("ctl00_TopMenuWebUserControl1_SearchTextBox"), "focus", clearSearchBox);
    Event.observe($("ctl00_TopMenuWebUserControl1_SearchTextBox"),"keydown", submitSearch);
}

function clearSearchBox()
{
    $("ctl00_TopMenuWebUserControl1_SearchTextBox").value = '';
}

function submitSearch(e)
{
    if(e.which || e.keyCode)
    {
        if ((e.which == 13) || (e.keyCode == 13))
        {
            __doPostBack('ctl00$TopMenuWebUserControl1$SearchButtonLinkButton','');
            return false;
        }
    }
    else
    {
        return true
    }
}
Event.observe(window, 'load', init);
//__doPostBack('ctl00$TopMenuWebUserControl1$SearchButtonLinkButton','')