Use this html to get the clicked element:
<div class="row" style="padding-left:21px;">
<ul class="nav nav-tabs" style="padding-left:40px;">
<li class="active filter"><a href="#month" onclick="Data('month', this)">This Month</a></li>
<li class="filter"><a href="#year" onclick="Data('year', this)">Year</a></li>
<li class="filter"><a href="#last60" onclick="Data('last60', this)">60 Days</a></li>
<li class="filter"><a href="#last90" onclick="Data('last90', this)">90 Days</a></li>
</ul>
</div>
Script:
function Data(string, el)
{
$('.filter').removeClass('active');
$(el).parent().addClass('active');
}