jQuery实现列表自动滚动循环滚动展示新闻

<div id="news">
<ul>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="aaaaaaaaaaaaaaa">aaaaaaaaaaaaaaa</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="bbbbbbbbbbbbbbb">bbbbbbbbbbbbbbb</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="ccccccccccccccc">ccccccccccccccc</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="ddddddddddddddd">ddddddddddddddd</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="eeeeeeeeeeeeeee">eeeeeeeeeeeeeee</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="fffffffffffffff">fffffffffffffff</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" title="ggggggggggggggg">ggggggggggggggg</a></li>
</ul>
</div>

ui,li {
list-style: none;
}
#news{
height: 75px;
overflow: hidden;
}

$(function() {
var $this = $("#news");
var scrollTimer;
$this.hover(function() {
clearInterval(scrollTimer);
}, function() {
scrollTimer = setInterval(function() {
scrollNews($this);
}, 2000);
}).trigger("mouseleave");

function scrollNews(obj) {
var $self = obj.find("ul");
var lineHeight = $self.find("li:first").height();
$self.animate({
"marginTop": -lineHeight + "px"
}, 600, function() {
$self.css({
marginTop: 0
}).find("li:first").appendTo($self);
})
}
})