我的为什么运行不了？各位大神帮我看看
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>jQuery动画特效</title>
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js" type="text/javascript"></script>
<style>
div{
left:150px;
position:absolute;
border:1px solid red;
}
</style>
</head>
<body>
<input id="btn1" type="button" value="左移" />
<input id="btn2" type="button" value="右移" />
<div >123</div>
<script type="text/javascript">
$(function(){
$("#btn1").bind("click",function(){
$("div").animate({
left: "-=50px";
},3000);
});
$("#btn2").bind("click",function(){
$("div").animate({
left: "+=50px";
},3000);
});
});
</script>
</body>
</html>
