jquery特效：无缝向上循环滚动列表

效果呈现

<div class="slide-title">
<span>title1</span>
<span>title2</span>
<span>title3</span>
</div>
<div class="slide-container"><!--css设置时，注意高度是显示多少个item,如：item的高度是30px，显示3个，高度则是 3*30 = 90px -->
<ul class="slide-list js-slide-list">
<li class="odd"><span>item1</span><span>item1</span><span>item1</span></li>
<li class="even"><span>item2</span><span>item2</span><span>item2</span></li>
<li class="even"><span>item2</span><span>item2</span><span>item2</span></li>
</ul>
</div>

var doscroll = function(){
var $parent = $('.js-slide-list');
var $first = $parent.find('li:first');
var height = $first.height();
$first.animate({
height: 0   //或者改成： marginTop: -height + 'px'
}, 500, function() {// 动画结束后，把它插到最后，形成无缝
$first.css('height', height).appendTo($parent);
// $first.css('marginTop', 0).appendTo($parent);
});
};
setInterval(function(){doscroll()}, 2000);