tumblr effects using fullpage.js callbacks

callbacks.js

onLeave: function(index, nextIndex, direction){
    if(nextIndex === 2){
        animationCont++;

        //forcing the gift to start again
        $('.section-2-animation')
            .css('background-image', 'url(animation3.gif?v='+animationCont+')');
    }
},
afterLoad: function(anchorLink, index){
    $('.blogs-graphic').toggleClass('active', (index === 3));
},
afterRender: function(){
    //forcing visual render of the element to we can apply the transition
    $('.section-1-whatIs')[0].clientHeight;
    $('.section-1-bg')[0].clientHeight;

    $('.section-1-bg, .section-1-whatIs, .section-1-content').addClass('active');
}