just a stupid simple jquery thing for styles on scroll

scrollbar.js

// This simple jquery script adds a class to an element once it reaches the bottom of a container (for example, a navbar switching colors once it reaches a new section on the page

$(window).scroll(function() {    
    var scroll = $(window).scrollTop();
    var topofDiv = $(".banner").offset().top; //use the element you want to limit the styles to
    var height = $(".banner").outerHeight(); 
     
    if (scroll >= (topofDiv + height) - 80) { // the -80 should be the height of the container that's changing
          $("#topNav").addClass("scrolled"); // this is where you add the new class for the element you want to change
      } else {
          $("#topNav").removeClass("scrolled");
      }
});