function oncervenamenu(imgname){
	document.getElementById(imgname).src = eval(imgname + "_gr" + ".src"); 
}

function oncernamenu(imgname){
	document.getElementById(imgname).src = eval(imgname + "_bk" + ".src");
}

function offbilamenu(imgname){
	document.getElementById(imgname).src = eval(imgname + "_gw" + ".src");
}

function offcernamenu(imgname){
	document.getElementById(imgname).src = eval(imgname + "_bk" + ".src");
}