查看“BootStrap Tool Tips”的源代码

        <div class="tooltip-demo">
          <div class="bs-example-tooltips">
            <div class="btn btn-default" data-toggle="tooltip" data-placement="left" title=""
            data-original-title="Tooltip on left">Tooltip on left</div>
            <div class="btn btn-default" data-toggle="tooltip" data-placement="top" title="" data-original-title="Tooltip on top">
            Tooltip on top</div>
            <div class="btn btn-default" data-toggle="tooltip" data-placement="bottom" title=""
            data-original-title="Tooltip on bottom">Tooltip on bottom</div>
            <div class="btn btn-default" data-toggle="tooltip" data-placement="right" title=""
            data-original-title="Tooltip on right">Tooltip on right</div>
          </div>
        </div>

        <p>This functionility can also be used in text, hovering over certain 
        <span class="pointer" data-toggle="tooltip" data-placement="top" title=""
        data-original-title="Tooltip on Top"><strong>words</strong></span> will produce the Tool Tip. You can also do
        the same 
        <span class="pointer" data-toggle="tooltip" data-placement="bottom" title=""
        data-original-title="Tooltip on Bottom"><strong>underneath</strong></span>. Tool Tips can be also be shown to
        the 
        <span class="pointer" data-toggle="tooltip" data-placement="left" title=""
        data-original-title="Tooltip on Left"><strong>left</strong></span>, or to the 
        <span class="pointer" data-toggle="tooltip" data-placement="right" title=""
        data-original-title="Tooltip on Right"><strong>right</strong></span>.</p>