bootstrap 下拉菜单改为鼠标悬停弹出效果

修改下拉菜单样式

<style type="text/css">
	.navbar .nav > li .dropdown-menu {
		margin: 0;
	}
	.navbar .nav > li:hover .dropdown-menu {
		display: block;
	}
</style>

<nav class="navbar navbar-default">
  <div class="container">
    <!-- 导航条logo部份 -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">LOGO</a>
    </div>

    <!-- 导航条菜单和表单部份 -->
    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav">
        <li><a href="#">菜单名称<span class="sr-only">(current)</span></a></li>
        <li><a href="#">菜单名称</a></li>
        <li class="dropdown">
            <a href="#">下拉菜单<span class="caret"></span></a>
          <ul class="dropdown-menu">
            <li><a href="#">二级菜单</a></li>
            <li><a href="#">二级菜单</a></li>
            <li><a href="#">二级菜单</a></li>
            <li role="separator" class="divider"></li>
            <li><a href="#">二级菜单</a></li>
            <li role="separator" class="divider"></li>
            <li><a href="#">二级菜单</a></li>
          </ul>
        </li>
      </ul>
      <ul class="nav navbar-nav navbar-right">
        <li><a href="#">投稿</a></li>
      <form class="navbar-form navbar-left">
        <div class="form-group">
          <input type="text" class="form-control" placeholder="Search">
        </div>
        <button type="submit" class="btn btn-default">搜索</button>
      </form>
      </ul>
    </div><!-- /.navbar-collapse -->
  </div><!-- /.container-fluid -->
</nav>