On scroll add class

  $(window).scroll(function() {
    var winTop = $(this).scrollTop();
    $('.insight_post_wrap .row').each(function() {
      var eleID = $(this).attr('[data-attr="scroll"]');
      var eleTop = $(this).offset().top - 56;
      var eleHeight = $(this).height();
      var eleTopOffset = eleTop + eleHeight;
      $('.insight_post_wrap .post-side-menu ul>li>a').each(function() {
        var linkID = $(this).attr('href').indexOf('#') && $(this).attr('href').split('#')[1];
        if (linkID != undefined) {
          if (eleID === linkID) {
            if (winTop >= eleTop && winTop <= eleTopOffset) {
              $(this).parent().addClass('bookmark-active');
            } else {
              $(this).parent().removeClass('bookmark-active');
            }
          }
        }
      });
    });
  });