哪里错了？
<title>无标题文档</title>
</head>
<style>
#div1{width:200px;
height:200px;
background:red;
position:absolute;
left:0;
top:200px;
}
</style>
<script>
window.onload=function(){
var oDiv=document.getElementById("star");
star.onclick= function(){
starmove(300);
}
}
var timer=null
function starmove(iTarget){
clearInterval(timer);
var oDiv=document.getElementById("div1");
timer=setInterval(function(){
if(oDiv.offsetLeft==iTarget){
clearInterval(timer);
}else{
oDiv.style.left = oDiv.offsetLeft+speed+"px";
}
},30)
}
</script>
<body>
<input id=star type="button" value="开始"/>
<div id=div1>
</div>
</body>
</html>
