javascript - Bootstrap 3 with Masonary 3 column format wrapping -

i using masonary boostrap 3. instead of 3 columns showing, 3rd col wrapping below.

here sample code , screenshot. idea why col-md-3, col-md-5 , col-md-3 not showing on 1 line

<div id="mason">     <div class="container">         <div class="row">              <div class="col-md-4 item">                  <!--some content-->              </div>              <div class="col-md-5 item">                  <!--some content-->             </div>              <div class="col-md-3 item">                  <!--some content-->              </div>           </div>     </div> </div>   $(document).ready(function(){    var $container = $('#mason');    $container.masonry({       itemselector        : '.item',       columnwidth         : '.item',       transitionduration  : 0     }); });