function hoverOn (imageID){
	imageObj=document.all? document.all[imageID] : document.getElementById(imageID);
	imageObj.src="images/nav/" +  imageID + "_2.png";
}

function hoverOff (imageID){
	imageObj=document.all? document.all[imageID] : document.getElementById(imageID);
	imageObj.src="images/nav/" + imageID + "_1.png";
}