// mouseover function
function rollOverFunc(imgName) {
	if (document.images){
		document.images[imgName].src = 'img/nav/' + imgName + '_r.png';
	}
}

// mouseout function
function rollOutFunc(imgName) {
	if (document.images)
		document.images[imgName].src = 'img/nav/' + imgName + '.png';
}