function rollon(whichtab)
	{
	 document.getElementById('nt_' + whichtab).src = 'images/' + whichtab + "_navtabhover.jpg"
	}

	function rolloff(whichtab)
	{
	 document.getElementById('nt_' + whichtab).src = 'images/' + whichtab + "_navtaboff.jpg"
	}

	function rollonhome(whattab)
	{
	 document.getElementById('nt_' + whattab).src = 'images/' + whattab + "_hometabhover.jpg"
	}

	function rolloffhome(whattab)
	{
	 document.getElementById('nt_' + whattab).src = 'images/' + whattab + "_hometaboff.jpg"
	}