The title attribute will be the content of the caption by default, you can change it by the caption option.

<div id="container">
    <div class="item" data-caption="this is the caption"></div>
    <div class="item" data-caption="this is the caption"></div>
    <div class="item" data-caption="this is the caption"></div>
    ...
</div>

 $(function() {

     $('#container').sliphover({
         target: '.item',
         caption: 'data-caption'
     });
 })