<ul class="dropdown-menu" role="menu">
<li class="vloading active"><a href="#">50</a></li>
<li class="vloading "><a href="#">100</a></li>
<li class="vloading "><a href="#">200</a></li>
</ul>
$(document).on('click', '.dropdown-menu li', function(e) {
var $li = $(this);
$li.siblings(".active").removeClass('active');
$li.addClass('active');
});