//menu
$(document).ready(function(){
  
  $('li.mainlevel').mousemove(function(){
  $(this).find('ul').slidedown(0);//you can give it a speed
  });
  $('li.mainlevel').mouseleave(function(){
  $(this).find('ul').slideup(0);
  });
  
});

//懒人图库 www.lanrentuku.com