function $(id){   
    return document.getElementById(id);
}
function SetMenuBackground(tableCell)
{
    tableCell.style.backgroundImage = tableCell.style.backgroundImage.indexOf('btnbg.jpg')!=-1 ? tableCell.style.backgroundImage='url(/images/btnbghover.jpg)' : tableCell.style.backgroundImage='url(/images/btnbg.jpg)';
}