sfHover = function() {
        var menuItems = YAHOO.util.Dom.getChildren('nav');
  YAHOO.util.Event.addListener(menuItems, "mouseover", function(){YAHOO.util.Dom.addClass(this, 'sfhover'); YAHOO.util.Dom.setStyle(this, 'z-index', '9999');});
        YAHOO.util.Event.addListener(menuItems, "mouseout", function(){YAHOO.util.Dom.removeClass(this, 'sfhover');});
}
if (window.attachEvent) YAHOO.util.Event.onDOMReady(sfHover);