javascript - Scrollify.js add class on current section -

am trying add 'active' class on current section in page using scrollify.js.

am able index value, not section id or section class! how current section's id or class.

here sample code tried achieve.

<section id="first" data-section="first" class="scroll-section"> </section>  before:function(index, sections) {     alert(index); }, 

this return index value. trying section id first.

thanks in advance.

call $.scrollify.current() returns current section.