我遇到了bootstrap问题 - 当我点击切换按钮时，折叠的导航栏没有显示。折叠的导航栏工作，但div已折叠隐藏，但为什么？ 任何人都可以帮助我 - 这对我来说很愉快。
这是我的代码：
<nav class="navbar navbar-default navbar-fixed-top fhmm" role="navigation">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
<span class="sr-only">Navigation ein-/ausblenden</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div id="navbar" class="collapse navbar-collapse">
<a href="http://webtest.igpp.de/german/welcome2.html" class="navbar-brand" href="welcome.htm"></a>
</div>
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<ul class="nav navbar-nav navbar-right">
<li><a href="welcome.htm">Startseite</a></li>
<!-- Mega Menu -->
<li class="dropdown fhmm-fw"><a href="#" data-toggle="dropdown" class="dropdown-toggle">Forschung <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-large row">
<li class="col-sm-8">
<ul>
<li><a href="/german/NEF.html"><h3 class="title">Naturwissenschaftlicher und Experimenteller Forschungsbereich</h3></a></li>
<li><span class="padding"><a href="/german/NEF/duale-aspekte_monismus.html">Duale-Aspekte Monismus</a></span></li>
<li><span class="padding"><a href="/german/NEF/Wahrnehmung_und_Kognition.html">Wahrnehmung und Kognition</a></span></li>
<li><span class="padding"><a href="/german/NEF/Wahrnehmung_und_Kognition.html">Zeitwahrnehmung und Zeitbewusstsein</a></span></li>
<li><a href="/german/SKF.html"><h3 class="title">Sozial und kulturwissenschaftlicher Forschungsbereich</h3></a></li>
<li><span class="padding"><a href="/SKF/sozialwissenschaft.html">Empirische Kultur- und Sozialforschung</a></span></li>
<li><span class="padding"><a href="/german/SKF/kulturwissenschaft.html">Kulturwissenschaftliche und wissenschaftshistorische Forschung</a></span></li>
<li> <span class="padding"><a href="/german/SKF.html">Sozial- und kulturwissenschaftlicher Forschungsbereich</a></span></li>
<li><h3 class="title"><a href="/german/counsel/AgE_forschung.html">Forschungsbereich "Außergewöhnliche Erfahrungen (AgE)"</a></h3></li>
<li><h3 class="title"><a href="/german/welcome-sidebar.htm">Klinische und Physiologische Psychologie</a></h3></li>
</ul>
</li>
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="#">Externe Forschung</a></h3></li>
<li><span class="padding"><a href="http://www.uni-giessen.de/cms/fbz/fb06/psychologie/weitere-inst/bion">BION</a></span></li>
</ul>
</li>
</ul>
</li>
<!-- list elements -->
<li class="dropdown fhmm-fw"><a href="#" data-toggle="dropdown" class="dropdown-toggle">Beratung <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-large row">
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="/german/counsel/info.htm">Beratung</h3></a></li>
<li><h3 class="title"><a href="/german/counsel/ueberuns.htm">Wer wir sind</a></h3></li>
<li><h3 class="title"><a href="/german/counsel/infostud.htm">Information für Studierende</a></h3></li>
</ul>
</li>
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="/german/counsel/grundsaetze.htm">Grundsätze</a></h3></li>
<li><h3 class="title"><a href="/german/counsel/erfahrungen.htm">Außergewöhnliche Erfahrungen</a></h3><li>
<li><h3 class="title"><a href="/german/counsel/beratunginfo.htm">Beratung und Information</a></h3></li>
</ul>
</li>
</ul><!-- end dropdown-menu -->
</li><!-- end dropdown fhmm-fw -->
<!-- list elements -->
<li class="dropdown fhmm-fw"><a href="#" data-toggle="dropdown" class="dropdown-toggle">Archiv <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-large row"> <li class="col-sm-4">
<li class="col-sm-4">
<ul>
<li><a href="/german/archive/info.htm"><h3 class="title">Überblick</h3></a></li>
<li><h3 class="title"><a href="/german/archive/archiv.htm">Bestände</a></h3></li>
<li><h3 class="title"><a href="/german/archive/links.htm">Archiv-Links</a></h3></li>
<li><h3 class="title"><a href="/german/archive/StudienmitArchivunterlagen.htm">Entstandene Arbeiten</a></h3></li>
</ul>
</li>
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="/german/archive/info.htm#pers">Mitarbeiter</a></h3></li>
<li><h3 class="title"><a href="/german/archive/info.htm#pub">Veröffentlichungen</a></h3></li>
<li><h3 class="title"><a href="/german/archive/ben_ord.htm">Benutzungsordnung</a></h3></li>
</ul>
</li>
</ul><!-- end dropdown-menu -->
</li><!-- end dropdown fhmm-fw -->
<li class="dropdown fhmm-fw"><a href="#" data-toggle="dropdown" class="dropdown-toggle">Bibliothek <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-large row">
<li class="col-sm-4">
<ul>
<li><a href="/german/archive/info.htm"><h3 class="title">Überblick</h3></a></li>
<li><h3 class="title"><a href="/german/archive/archiv.htm">Mitarbeiter</a></h3></li>
<li> <h3 class="title"><a href="/german/archive/links.htm">Bibliothek</a></h3></li>
</ul>
</li>
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="/german/archive/info.htm#pers">Zeitschrift</a></h3></li>
<li><h3 class="title"><a href="/german/archive/info.htm#pub">Veröffentlichungen</a></h3></li>
</ul>
</li>
</ul><!-- end dropdown-menu -->
</li><!-- end dropdown fhmm-fw -->
<li class="dropdown fhmm-fw"><a href="#" data-toggle="dropdown" class="dropdown-toggle">Aktuelles <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-large row">
<li class="col-sm-4">
<ul>
<li><a href="/common/events.htm#news"><h3 class="title">News</h3></a></li>
<li><h3 class="title"><a href="/common/events.htm#colloq">IGPP-Colloquium</a></h3></li>
</ul>
</li>
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="/common/events.htm#other">Other Events</a></h3></li>
</ul>
</li>
</ul><!-- end dropdown-menu -->
</li><!-- end dropdown fhmm-fw -->
<li class="dropdown fhmm-fw"><a href="#" data-toggle="dropdown" class="dropdown-toggle">Über uns <b class="caret"></b></a>
<ul class="dropdown-menu dropdown-menu-large row">
<li class="col-sm-4">
<ul>
<li><a href="/german/contact.htm"><h3 class="title">Kontakt</h3></a></li>
<li><h3 class="title"><a href="/german/mitarbeiter.htm">Mitarbeiter</a></h3></li>
<li><h3 class="title"><a href="/german/struct.htm">Organisationsstruktur</a></h3></li>
</ul>
</li>
<li class="col-sm-4">
<ul>
<li><h3 class="title"><a href="/german/reports.htm">Tätigkeitsberichte</a></h3></li>
<li><h3 class="title"><a href="/german/where.htm">Wegbeschreibung</a></h3></li>
</ul>
</li>
</ul>
</li><!-- end dropdown fhmm-fw -->
</ul><!-- end nav navbar-nav -->
</div>
</div>
</nav><!-- end navbar navbar-default fhmm -->