jquery实现更多内容效果

写个“更多内容的展开/收起”的js
代码如下：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>jQuery实现收起展开功能 - 何问起</title><base target="_blank" />
<meta charset="utf-8" />
<style>
a{color:darkgreen}
.hovertreeContent{width:300px;text-indent:2em;margin:5px auto;height:60px;overflow:hidden;position:relative;border:1px solid silver;}
.hewenqiToggle{height:20px;background-color:#f0f0f0;border-top:1px solid silver;position:absolute;bottom:0px;width:100%;}
.triangle-down-hovertree { width: 0; height: 0; border-left: 8px solid transparent; border-right: 8px solid transparent; border-top: 16px solid #999;position:absolute;right:0px;left:0px;margin:0px auto; top:2px;cursor:pointer;}
.triangle-up-hovertree { width: 0; height: 0; border-left: 8px solid transparent; border-right: 8px solid transparent; border-bottom: 16px solid #999; position:absolute;right:0px;left:0px;margin:0px auto;top:2px; }
</style>
<script src="http://hovertree.com/ziyuan/jquery/jquery-1.12.1.min.js"></script>

</head>
<body>
<div style="730px;margin:0px auto;text-align:center;">
<h2>jQuery实现收起展开功能</h2>
<a href="http://hovertree.com/h/bjaf/6sm1esjw.htm">原文</a> <a href="http://hovertree.com">首页</a> <a href="http://hovertree.com/texiao/">特效</a>
</div>
<div class="hovertreeContent">
受到网店的影响，服装店的生意逐渐有所下降，老板找何问起去谈，大概是准备跟上网购潮流，让何问起准备一下，
要在网上开网店，要为服装店建立网站。
何问起也没说自己经验不足，只说会积极准备。于是抓紧时间查找资料，学习练习。
<div class="hewenqiToggle"><span class="triangle-down-hovertree"></span></div>
</div>
<script>
$(".hewenqiToggle").on("click", function () {
if ($(".hewenqiToggle").css('position') == "absolute") {
$(".hovertreeContent").height("auto");
$(".hewenqiToggle").css({ "position": "relative" });
$(".hewenqiToggle").find("span").removeClass('triangle-down-hovertree').addClass('triangle-up-hovertree');
}
else
{
$(".hovertreeContent").height("60");
$(".hewenqiToggle").css({ "position": "absolute" });
$(".hewenqiToggle").find("span").removeClass('triangle-up-hovertree').addClass('triangle-down-hovertree');
}
})
</script>
</body>
</html>
转自：http://hovertree.com/h/bjaf/6sm1esjw.htm