CSS3 3D效果
不知道什么地方出错了，不翻页，谷歌显示”Cannot read property 'style' of null“，这个要怎么修改啊？？？
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>无标题文档</title>
<style type="text/css">
#my3d{
-webkit-perspective:800px;
-webkit-perspective-origin:50% 50%;
overflow:hidden;
}
#book{
width:400px;
height:400px;
margin:0 auto;
-webkit-transform-style:preserve-3d;
position:relative;
}
.page{
width:400px;
height:400px;
background-color:black;
color:white;
font-weight:bold;
font-size:380px;
line-height:380px;
text-align:center;
position:absolute;
}
#p1{
-webkit-transform-origin:bottom;
-webkit-transition:-webkit-transform 1s linear;
}
#p2,#p3,#p4,#p5,#p6{
-webkit-transform-origin:bottom;
-webkit-transition:-webkit-transform 1s linear;
-webkit-transform:rotateX(90deg);
}
#po{
text-align:center;
margin:40px auto;
}
</style>
<script type="text/javascript">
var index=1;
function next(){
if(index==6){
return;
}
var index=document.getElementById("p"+index);
index.style.webkitTransform="rotateX(-90deg)";
index++;
var nextindex=document.getElementById("p"+index);
nextindex.style.webkitTransform="rotateX(0deg)";
}
function pre(){
if(index==1){
return;
}
var index=document.getElementById("p"+index);
index.style.webkitTransform="rotateX(90deg)";
index--;
var preindex=document.getElementById("p"+index);
preindex.style.webkitTransform="rotateX(0deg)";
}
</script>
</head>
<body>
<div id="my3d">
<div id="book">
<div class="page" id="1">1</div>
<div class="page" id="p2">2</div>
<div class="page" id="p3">3</div>
<div class="page" id="p4">4</div>
<div class="page" id="p5">5</div>
<div class="page" id="p6">6</div>
</div>
</div>
<div id="po">
<a href="javascript:next()">next</a>
<a href="javascript:pre()">pre</a>
</div>
</body>
</html>
