<!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=utf-8" />
<title>无标题文档</title>
<style type="text/css">
*{margin：0；padding：0；}
#share{
top:200px;
width:200px;
height:100px;
left:-200px;
background:#0FF;
position:relative;
}
#small{
width:30px;
height:50px;
background:#C00;
left:200px;
position:absolute;
}
</style>
<script type="text/javascript">
window.onload=function(){
var share=document.getElementById('share');
share.onmouseover=function(){
move(10,0);
}
share.onmouseout=function(){
move(-10,-200);
}
}
var time=null;
function move(speed,target){
clearInterval(time);
var share=document.getElementById('share');
time=setInterval(function(){
if(share.offsetLeft==target){clearInterval(time);}
else{share.style.left=share.offsetLeft+speed+'px';}
}
,30)
}
</script>
</head>
<body>
<div id="share">
<div id="small"><span>分享</span></div>
</div>
</body>
</html>
*{margin：0；padding：0；}这一行出错了，你用的是中文字符下的符号,应该是这样的：
*{margin:0; padding:0;}