无法将寻呼机(导航栏)定位在jqGrid上方

.jqgrid-container {
  position: relative;
}

.navbar {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}

$('.navbar').css({
  position: 'absolute',
  top: $('.jqgrid-container').offset().top,
  left: $('.jqgrid-container').offset().left,
  width: $('.jqgrid-container').width()
});

$('.navbar').draggable({
  containment: '.jqgrid-container',
  scroll: false
});

<div class="container">
  <ul class="sortable">
    <li class="navbar">导航栏</li>
    <li class="jqgrid">jqGrid</li>
  </ul>
</div>

$('.sortable').sortable({
  items: 'li',
  handle: '.navbar'
});