折叠菜单栏，data-toggle="collapse"，为什么还是会默认显示呢

[w2362233]

<button type="button" data-toggle="collapse" data-target="#bs-example-navbar-collapse" aria-expanded="false" style="margin-right:60px">
<label class="ac-gn-menuicon-label" >
<span class="menuicon-bread menuicon-bread-top">
菜单
</span>
</label>
</button>
<div class="view" >


<div class="left-menu" id="bs-example-navbar-collapse" >
<header class="header">
<a class="navbar-brand" href="{$WEB_ROOT}/index.php" title="{$companyname}">{$companyname}</a>
</header>
<div class="left-menu-wrap">
<section class="menu">
<ul>
<li class="item {if $templatefile == 'clientareahome'}active{/if}">
<a href="clientarea.php"><i class="alico icon-menu"></i>{$LANG.clientareatitle}</a>
</li>