父页面的popover遮罩不能遮住子页面的上拉加载内容怎么办。。。

父页面

<header class="mui-bar mui-bar-nav">  
          <a class="mui-action-back mui-icon mui-icon-home mui-pull-left"></a>  
          <a class="mui-icon mui-icon-search mui-pull-right"></a>  
          <h1 class="mui-title">品牌库</h1>  
        </header>  
        <div class="mui-content">  
            <nav class="checkbar">  
                <div class="mui-pull-left mui-col-xs-6">  
                    <a href="#brandPopover">  
                        <span id="brandDropdown">品牌库</span>  
                        <span class="mui-icon mui-icon-arrowdown"></span>  
                    </a>  
                </div>  
                <div class="mui-pull-left mui-col-xs-6" id="goFilter"><a>筛选</a></div>  
            </nav>  
            <!--下拉刷新容器-->  
        </div>  
        <!--品牌库弹出层-->  
        <div id="brandPopover" class="mui-popover">  
              <ul class="mui-table-view" id="byBrand">  
                <li id="0" class="mui-table-view-cell">品牌库</li>  
                <li id="1" class="mui-table-view-cell">我创建的</li>  
                <li id="3" class="mui-table-view-cell">我贡献的</li>  
              </ul>  
        </div>

子页面：

<!--下拉刷新容器-->  
            <div id="pullrefresh" class="mui-content mui-scroll-wrapper">  
              <div class="mui-scroll">  
                <ul  id="content" class="mui-table-view mui-table-view-striped mui-table-view-condensed"></ul>  
              </div>  
              <div class="mui-loader mui-text-center" id="loading" style="padding-top:50px;"><span class="mui-icon mui-icon-spinner-cycle mui-spin"></span><br />加载中...</div>  
            </div>