js代码写完为什么点击没有效果 求解
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>海报画廊</title>
<style type="text/css">
*{padding:0;margin:0;}
body{background-color:#fff;
color:#555;
font-family:'Avenir Next','Lantinghei SC';
font-size: 14px;
-webkit-font-smoothing:antialiased;
}
.photo{
width:260px;
height:320px;
position: absolute;
z-index: 1;
box-shadow: 0 0 1px rgba(0,0,0,.01);
}
.photo .side{
width:100%;
height:100%;
background: #eee;
position: absolute;
top:0;
right:0;
padding: 20px;
box-sizing: border-box;
}
.photo .side-front{}
.photo .side-front .image{
width: 100%;
height: 250px;
line-height: 250px;
overflow:hidden;
}
.photo .side-front .image img{
widows: 100%;
}
.photo .side-front .caption{
text-align: center;
font-size: 16px;
line-height: 50px;
}
.photo .side-back{
color:#666;
font-size:14px;
line-height: 1.5em;
}
.photo_center{
left:50%;
top:50%;
margin:-160px 0 0 -130px;
z-index: 99;
}
.wrap{
width:100%;
height: 600px;
position: absolute;
top: 50%;
margin-top: -300px;
background:#333;
overflow: hidden;
-webkit-perspective:8000px;
}
.photo-wrap{
position: absolute;
width:100%;
height: 100%;
-webkit-transform-style:preserve-3d;
-webkit-transition:all .7s;
}
.photo-wrap .side-front{
-webkit-transform:rotateY(0deg);
}
.photo-wrap .side-back{
-webkit-transform:rotateY(180deg);
}
.photo-wrap .side{
-webkit-backface-visibility:hidden;
}
.photo_front .photo-wrap{
-webkit-transform:rotateY(0deg);
}
.photo_back .photo-wrap{
-webkit-transform:rotateY(180deg);
}
</style>
</head>
<body oneselectstart="return false;">
<div>
<div class="photo photo_center photo_front" onclick="turn(this)">
<div >
<div class="side side-front">
<p><img src="1 超能陆战队.jpg" style="width:240px;"/></p>
<p>超能陆战队</p>
</div>
<div class="side side-back">
<p>描述信息</p>
</div>
</div>
</div>
</div>
<script type="text/javascript">
function turen (elem){
var elem.className;
if(/photo_front/.test(cls)){
cls=cls.replace(/photo_front/,'photo_back');
}
else{
cls=cls.replace(/photo_back/,'photo_front');
}
return elem.className=cls;
}
</script>
</body>
</html>
