$(function(){
    $(window).scroll(function () { 
        var scrollValue = $(document).scrollTop(); 
        console.log(scrollValue); 
    });
    let scroll = '';
    $(window).on('scroll' , function(){
      scroll = $(window).scrollTop();
      if(scroll > 900){
        $('.sence').addClass('active');
      }else{
        $('.sence').removeClass('active');
      }
      if(scroll > 1200){
        $('.years~ul').addClass('active');
      }else{
        $('.years~ul').removeClass('active');
      }
      if(scroll > 1500){
        $('.years~ul.active').addClass('active2');
        $('.years').addClass('active');
      }else{
        $('.years~ul.active').removeClass('active2');
        $('.years').removeClass('active');
      }
      if(scroll > 1900){
        $('.years~ul.active.active2').addClass('active3');
      }else{
        $('.years~ul.active.active2').removeClass('active3');
      }
      if(scroll > 2200){
        $('.years~ul.active.active2.active3').addClass('active4');
      }else{
        $('.years~ul.active.active2.active3').removeClass('active4');
      }
      if(scroll > 2500){
        $('.years~ul.active.active2.active3.active4').addClass('active5');
      }else{
        $('.years~ul.active.active2.active3.active4').removeClass('active5');
      }
      if(scroll > 2800){
        $('.years~ul.active.active2.active3.active4.active5').addClass('active6');
      }else{
        $('.years~ul.active.active2.active3.active4.active5').removeClass('active6');
      }
      if(scroll > 3100){
        $('.years~ul.active.active2.active3.active4.active5.active6').addClass('active7');
      }else{
        $('.years~ul.active.active2.active3.active4.active5.active6').removeClass('active7');
      }
      if(scroll > 3250){
        $('.sence.active').addClass('stop');
      }else{
        $('.sence.active').removeClass('stop');
      }
    });
  });