在对应的div中，添加overflow,固定高度为400px
<div class="panel-body" style="height: 400px; overflow:scroll"><div style="border: 1px #000000; width: 90%; margin: 0 auto;"><span></span></div></div>
水平、垂直滚动条就都有了！也可固定width
垂直滚动条
<div class="panel-body" style="height: 400px; overflow-y:scroll"><div style="border: 1px #000000; width: 90%; margin: 0 auto;"><span></span></div></div>
