<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 示例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.cn/lib/bootstrap/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.5.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://www.w3schools.cn/lib/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h1>输入组大小</h1>
<p>将 .input-group-sm 类用于小型输入组，将 .input-group-lg 类用于大型输入组：</p>
<form>
<div class="input-group mb-3 input-group-sm">
<div class="input-group-prepend">
<span class="input-group-text">小</span>
</div>
<input type="text" class="form-control">
</div>
</form>
<form>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">默认</span>
</div>
<input type="text" class="form-control">
</div>
</form>
<form>
<div class="input-group mb-3 input-group-lg">
<div class="input-group-prepend">
<span class="input-group-text">大</span>
</div>
<input type="text" class="form-control">
</div>
</form>
</div>
</body>
</html>