<html>
<head>
<title>Bootstrap 实例 - 输入框组的大小</title>
<link href="https://libs.baidu.com/bootstrap/3.0.3/css/bootstrap.min.css" rel="stylesheet">
<script src="https://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
<script src="https://libs.baidu.com/bootstrap/3.0.3/js/bootstrap.min.js"></script>
</head>
<body>
<div style="padding: 100px 100px 10px;">
<form class="bs-example bs-example-form" role="form">
<div class="input-group input-group-lg">
<span class="input-group-addon">@</span>
<input type="text" class="form-control" placeholder="Twitterhandle">
</div><br>
<div class="input-group">
<span class="input-group-addon">@</span>
<input type="text" class="form-control" placeholder="Twitterhandle">
</div><br>
<div class="input-group input-group-sm">
<span class="input-group-addon">@</span>
<input type="text" class="form-control" placeholder="Twitterhandle">
</div>
</form>
</div>
</body>
</html>