mui导航菜单

新手。我做菜单导航时默认导航下的列表能出来，可点击其他菜单导航时，效果不出来，还包Uncaught TypeError: Cannot read property 'querySelector' of null错误，求大神指点

代码如下：
<div class="mui-off-canvas-wrap mui-draggable">

        <header class="mui-bar mui-bar-nav">  
            <a class="mui-icon mui-icon-left-nav mui-pull-left"></a>  
            <a href="#offCanvas" class="mui-icon mui-icon-bars mui-pull-right"></a>  
           <h1 class="mui-title">我审批的</h1>  
        </header>  

        <div style="height:50px;"></div>  

        <div>  
        <div id="segmentedControl" class="mui-segmented-control">  
            <a class="mui-control-item mui-active" id="daichuli"  href="#item1mobile">  
                    待处理  
            </a>  
            <a class="mui-control-item" id="yichuli" href="#item2mobile">  
                    已处理  
            </a>  
            <a class="mui-control-item" id="yichexiao" href="#item3mobile">  
                    已撤销  
            </a></div>  

            <div class="mui-content-padded">  
                <div class="mui-input-row mui-search">  
                    <span class="mui-icon mui-icon-search mui-pull-right"></span>  
                    <input type="search" class="mui-input-clear" placeholder="搜索" style="color: whitesmoke;" value="请输入关键字。。。。">  
                </div>  
           </div>  

      </div>  

    <div class="mui-content-padded">  
        <div id="item1mobile"   class="mui-control-content mui-active" >  
            <ul class="mui-table-view">  
                <li class="mui-table-view-cell">  
                        <a href="//ask.dcloud.net.cn/index-2-dels.html">第一个选项卡子项-1</a>  
                </li>  
                <li class="mui-table-view-cell">  
                        <a href="//ask.dcloud.net.cn/index-2-dels.html">第一个选项卡子项-2</a>  
                </li>  

            </ul>  
        </div>  

        <div id="item2mobile"  class="mui-control-content" >  
            <ul class="mui-table-view">  
                <li class="mui-table-view-cell">  
                        <a href="//ask.dcloud.net.cn/index-2-dels.html">第二个选项卡子项-1</a>  
                </li>  
                <li class="mui-table-view-cell">  
                        <a href="//ask.dcloud.net.cn/index-2-dels.html">第二个选项卡子项-2</a>  
                </li>  

            </ul>  
        </div>  

        <div id="item3mobile"   class="mui-control-content" >  
            <ul class="mui-table-view">  
                <li class="mui-table-view-cell">  
                        <a href="//ask.dcloud.net.cn/index-2-dels.html">第三个选项卡子项-1</a>  
                </li>  
                <li class="mui-table-view-cell">  
                        <a href="//ask.dcloud.net.cn/index-2-dels.html">第三个选项卡子项-2</a>  

            </ul>  
        </div>  

    </div>  

    </div>