/***************************
	* facilitates button rollovers. This function also assumes the naming convention
	* of variables for preloading the button images to be [imageName]_[pDir]
	* @param
	*	pImageName	- Name of the image as defined in "<img src"
	*	pDir	- direction "up" or "dn"
	****************************/
	function rollover(pImageName, pDir) {
		document.images[pImageName].src = eval(pImageName + "_" + pDir + ".src");
	}