3，解决bootstrap导航条居中显示的问题

<div class="navbar-collapse collapse" style="text-align: center;">
    <ul class="nav navbar-nav" style="display: inline-block;float: none;">
        <li class="">
            <a href="#">首页</a>
        </li>
        <li class="">
            <a href="#">加入我们</a>
        </li>
        <li class="">
            <a href="#">联系我们</a>
        </li>
    </ul>
</div>

<style>
.collapsing {
    -webkit-transition: none;
    transition: none;
    display: none;
}
</style>