function doRollover(theId,theImg)
{
	document.getElementById(eval("'nav"+theId.toString() + "'")).src = "images/nav/" + theImg + "_on.gif";
}	

function doRollout(theId,theImg)
{
	document.getElementById(eval("'nav"+theId.toString() + "'")).src = "images/nav/" + theImg + "_off.gif";
}