code: function (force) {
      var $overlay = $('.mdui-overlay');
  
      if (!$overlay.length) {
        return;
      }
  
      var level = force ? 1 : $overlay.data('overlay-level');
      if (level > 1) {
        $overlay.data('overlay-level', --level);
        return;
      }
  
      $overlay
        .data('overlay-level', 0)
        .removeClass('mdui-overlay-show')
        .data('isDeleted', 1)
        .transitionEnd(function () {
          if ($overlay.data('isDeleted')) {
            $overlay.remove();
          }
        });
    }
docs: 隐藏遮罩层
  @param force 是否强制隐藏遮罩