1 $("#menu1").bind("mouseover",function(){$("#menu1").attr("class","about_menu1");$("#mbtn_menu2").css("display","block")});
2 $("#menu1").bind("mouseout",function(){$("#menu1").attr("class","about_menu1_1");$("#mbtn_menu2").css("display","none"); });
2 $("#menu1").bind("mouseout",function(){$("#menu1").attr("class","about_menu1_1");$("#mbtn_menu2").css("display","none"); });
鼠标在下拉菜单移动时菜单会不断闪烁，说明不断触发了 mouseover 和 mouseout 事件。
解决方法：将 mouseover 改成 mouseenter，mouseout 改成 mouseleave。