Question

I’d like to add a class to an element when a user first scrolls away from the top of the page. If the user then scrolls back up and hits the top of the page I’d like that class removed.

Use of jQuery in the solution is fine.

Answer 1

try

$(window).scroll(function() {    

    $("id or class").removeClass("active");

    var scroll = $(window).scrollTop();

    if (scroll <= 500) {
        $("#one").addClass("active");
    }
    else if (scroll <= 1000) {
        $("#tow").addClass("active");
    }
    else {
        $("#three").addClass("active");
    }
}