平板电脑上的Android浏览器上没有显示bootstrap折叠菜单

Question

在所有浏览器上工作请点击此处：

但仅在平板电脑Android浏览器上显示为：

有没有人知道如何解决这个问题？什么似乎是问题？

这是我的代码：

<nav class="navbar navbar-inverse padding-bottom-26" role="banner">
            <div class=" padding-11">
                <div class="navbar-header margin-header">
                    <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                        <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="<?php echo site_url('home') ?>"><img src="public/images/syscom-logo.png" alt="logo" class="img-width"></a>
                </div>
                <div class="collapse navbar-collapse navbar-right float-left-ul">
                    <ul class="nav navbar-nav ">
                        <li class="<?php if ($activePage === 'home' || $activePage === FALSE) echo 'active' ?>"><a href="<?php echo site_url('home') ?>">Home</a></li>
                        <li class="<?php if ($activePage === 'about-us') echo 'active' ?>"><a href="<?php echo site_url('about-us') ?>">About Us</a></li>
                        <li class="dropdown <?php if ($activePage === 'our-services') echo 'active' ?>">
                            <a href="<?php echo site_url('our-services') ?>" class="dropdown-toggle" >Services <i class="fa fa-angle-down"></i></a>
                            <ul class="dropdown-menu">
                                <li><a href="<?php echo site_url('our-services') ?>#domain">Domain Names</a></li>
                                <li><a href="<?php echo site_url('our-services') ?>#host">Web Hosting</a></li>
                                <li><a  href="<?php echo site_url('our-services') ?>#bpa">Business Process Automation</a></li>
                                <li><a  href="<?php echo site_url('our-services') ?>#support">Technical Support</a></li>
                            </ul>
                        </li>
                        <li class="<?php if ($activePage === 'our-solutions') echo 'active' ?>"><a href="<?php echo site_url('our-solutions') ?>">Solutions</a></li>
                        <li class="<?php if ($activePage === 'our-work') echo 'active' ?>"><a href="<?php echo site_url('our-work') ?>">Our Work</a></li>
                        <li class="<?php if ($activePage === 'join-our-team') echo 'active' ?>"><a href="<?php echo site_url('join-our-team') ?>">Join Our Team</a></li>
                        <li class="<?php if ($activePage === 'contact-us') echo 'active' ?>"><a href="<?php echo site_url('contact-us') ?>">Contact Us</a></li>

                    </ul>
                </div>
            </div>
        </nav>