function setnav()
{
	if (window.thtrSect)
		self.document.images["t" +thtrSect].src = "img/thtr_nav_" + thtrSect + "-on.gif";
		self.document.images["b" +thtrSect].src = "img/thtr_nav_" + thtrSect + "-on.gif"
}

function rollon(name)
{
	if(self.document.images) 
		var imgName = self.document.images[name].src		
		var imgLen = imgName.length
		var imgExt = imgName.slice(imgLen - 4)
		imgName = imgName.slice(0, imgLen - 4)
		if (imgName.slice(imgName.length - 3) !== "-on")
			self.document.images[name].src = imgName + "-over" + imgExt;
}

function rolloff(name)
{
	if(self.document.images) 
		var imgName = self.document.images[name].src
		var imgLen = imgName.length
		var imgExt = imgName.slice(imgLen - 4)
		imgName = imgName.slice(0, imgLen - 4)
		if (imgName.slice(imgName.length - 5) == "-over")
			self.document.images[name].src = imgName.slice(0, imgName.length -5) + imgExt;
}