function chg_img(val,srcObj) {
	var menu_div = document.getElementById('menu_div').value;
	if("sub"+val !="sub"+ menu_div) {
		if(srcObj.indexOf('_off')>0) {
			document.getElementById(val).src = srcObj.replace('_off','_on');
		} else {
			document.getElementById(val).src = srcObj.replace('_on','_off');
		}
	}
}