function menuHover() {
 menuTmp = window.event.srcElement;
 if (menuTmp.menu) {
  if (menuTmp.className ==  menuTmp.menu + "_off") {
   menuTmp.className = menuTmp.menu + "_over";
   return(0);
  }
  if (menuTmp.className ==  menuTmp.menu + "_over") {
   menuTmp.className = menuTmp.menu + "_off";
   return(0);
  }
 }
}

document.onmouseover = menuHover;
document.onmouseout = menuHover;