实例如下所示：
<!DOCTYPE html>
<html>
<head>
<title></title>
<style type=text/css>
.scrolldiv{
width: 500px;
height: 400px;
margin: 10px auto;
background: #f00;
overflow-y: scroll;
padding: 10px;
}
</style>
</head>
<body>
<div class=scrolldiv id=testDiv>
<br><br><br><br><br
