bootstrap导航栏中的按钮

<nav class="navbar navbar-default" role="navigation">
<div class="navbar-header">
<a class="navbar-brand" href="#">W3Cschool</a>
</div>
<div>
<form class="navbar-form navbar-left" role="search">
<div class="form-group">
<input type="text" class="form-control" placeholder="Search">
</div>
<button type="submit" class="btn btn-default">提交按钮</button>
</form>
<button type="button" class="btn btn-default navbar-btn">
导航栏按钮
</button>
</div>
</nav>