Single side scroll reveal animation

Single side scroll reveal animation

//scroll direction and anim
var scrollDirection = function (elem) {
  $(window).on('DOMMouseScroll mousewheel', function (event) {
    if (event.originalEvent.detail > 0 || event.originalEvent.wheelDelta < 0) {
      if (elem.parent().isOnScreen()) {
        console.log("malar");
        elem.each(function () {
          var $this = $(this);
          var delay = $this.attr("data-delay");
          setTimeout(function () {
            $this.addClass("show");
          }, delay);
        });
      }

    } else {
      if (elem.isOnScreen() == false) {
        elem.removeClass("show");
      }
    }
  });
}($('.single-anim-inner'));