                        课程
                    
                        /前端开发
                        
                            /JavaScript
                        
                        /JS动画效果

为什么这个没有动画效果啊

<!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">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>

<style type="text/css">
#move{
position:relative;
width:50px;
height:60px;
background:#00CC33;
top:75px;
left:-30px;
}
</style>
<style>
<script>
window.onload = function(){
var oDiv = document.getElementById('move');
oDiv.onmouseover = function(){
startmove();
}
}
function startmove(){
var oDiv = document.getElementById('move');
setInterval(function(){
oDiv.style.left = oDiv.offsetLeft+10+'px';
},30);
}
</script>
</style>
</head>
<body>
<div id="move">hello
</div>
</body>
</html>