<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div class="container"> <ul class="nav navbar-nav"> <li class="active"><a href="#">Home</a></li> <li> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Menu 1 <b class="caret"></b></a> <ul class="dropdown-menu multi-level"> <li><a href="#">one</a></li> <li><a href="#">two</a></li> <li><a href="#">three</a></li> <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li><a href="#">Action</a></li> </ul> </li> <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li><a href="#">Action</a></li> <li><a href="#">Action</a></li> <li><a href="#">Action</a></li> <li><a href="#">Action</a></li> <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li><a href="#">one</a></li> <li><a href="#">two</a></li> <li><a href="#">three</a></li> </ul> </li> </ul> </li> </ul> </li> </ul> </li> <li> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Menu 1 <b class="caret"></b></a> <ul class="dropdown-menu multi-level"> <li><a href="#">one</a></li> <li><a href="#">two</a></li> <li><a href="#">three</a></li> <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li><a href="#">Action</a></li> <!-- <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li class="inner-dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a> <ul class="dropdown-menu"> <li><a href="#">one</a></li> <li><a href="#">two</a></li> <li><a href="#">three</a></li> </ul> </li> </ul> </li> --> </ul> </li> </ul> </li> </ul> </div>

.inner-dropdown { position: relative; } .inner-dropdown .dropdown-menu { top: 0; left: 100%; margin-top: -1px; width: 200px; /*height: calc(100vh - 150px); overflow-y: scroll;*/ } .inner-dropdown .caret { -webkit-transform: rotate(-90deg) translateY(-50%); -moz-transform: rotate(-90deg) translateY(-50%); -o-transform: rotate(-90deg) translateY(-50%); -ms-transform: rotate(-90deg) translateY(-50%); transform: rotate(-90deg) translateY(-50%); position: absolute; top: 44%; right: 5px; } .inner-dropdown { position: relative; } .inner-dropdown>.dropdown-menu { top: 0; left: 100%; margin-top: -6px; margin-left: -1px; -webkit-border-radius: 0 6px 6px 6px; -moz-border-radius: 0 6px 6px; border-radius: 0 6px 6px 6px; } .inner-dropdown:hover>.dropdown-menu { display: block; } .inner-dropdown>a:after { display: block; content: " "; float: right; width: 0; height: 0; border-color: transparent; border-style: solid; border-width: 5px 0 5px 5px; border-left-color: #ccc; margin-top: 5px; margin-right: -10px; } .inner-dropdown:hover>a:after { border-left-color: #fff; } .inner-dropdown.pull-left { float: none; } .inner-dropdown.pull-left>.dropdown-menu { left: -100%; margin-left: 10px; -webkit-border-radius: 6px 0 6px 6px; -moz-border-radius: 6px 0 6px 6px; border-radius: 6px 0 6px 6px; }