// For mouseover
function move_in(img_name)	{
   	var ls_src = "images/" + img_name + "_on.gif"
	document[img_name].src=ls_src;
}

// For mouseout
function move_out(img_name) {
   	var ls_src = "images/" + img_name + "_off.gif"
	document[img_name].src=ls_src;
}