2015-06-02 js移入移出的动画渐变

<div href="" class=‘layer‘>
    	<div class=‘prev‘></div>
</div>
//注意要div包裹，html规范

.layer{width: 100px;height: 180px;border: 1px solid #000;}
.prev{opacity:0;width: 62px;height: 62px;position: absolute;top: 50px;left: 0;background:  url(../images/1.jpg) 0 0 no-repeat;}



$(‘.layer‘).on(‘mouseenter‘, function(){
   $(‘.prev‘).animate({‘opacity‘:‘1‘},40)
}).on(‘mouseleave‘, function(){
  $(‘.prev‘).animate({‘opacity‘:‘0‘},40)
})
//hover等于mouseenter和mouseleave一样


移入移出的动画渐变