<!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" xml:lang="en"><head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title></title>
</head>
<body>
<script type="text/javascript" src="jquery-1.7.1.min.js"></script>
<div>
<input type="text" value="" name="username" class="username" />
<input type="button" value="点击获取输入框的值" name="sub" onclick="getData();" />
<script type="text/javascript">
function getData(){
var username = $.trim($(".username").val());
alert(username);
}
</script>
</div>
</body>
</html>