引导3拆分下拉按钮创建

<link href="https://stackpath.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>
<li>
    <div class="btn-group">
    	<button type="button" class="btn btn-default navbar-btn">Action</button>
    	<button type="button" data-toggle="dropdown" class="btn btn-default navbar-btn dropdown-toggle"
    				aria-haspopup="true" aria-expanded="false">
    		<span class="caret"></span>
    		<span class="sr-only">Toggle Dropdown</span>
    	</button>
    	 <ul class="dropdown-menu">
    		<li><a href="#">Action</a></li>
    		<li><a href="#">Another action</a></li>
    		<li><a href="#">Something else here</a></li>
    		<li role="separator" class="divider"></li>
    		<li><a href="#">Separated link</a></li>
    	</ul>
    </div>
</li>