if (document.images)
{
	navOn = new Image();
	navOn.src = "images/nav/on.gif";
	navOff = new Image();
	navOff.src = "images/nav/off.gif";
}

function imgOn(imgName)
{
		document[imgName].src = navOn.src;
}			    

function imgOff(imgName)
{
	if (document.images)
	{
		document[imgName].src = navOff.src;
	}
}