document.addEventListener("DOMContentLoaded", function(event) {
    //Scroll to top START
    var currentYOffset = window.pageYOffset;
    if ( currentYOffset > 0 ) {
        document.getElementById("scroll-to-top").style.display = 'block';
    } else {
        document.getElementById("scroll-to-top").style.display = 'none';
    }

    window.addEventListener("scroll", function (event) {
        var scroll = this.scrollY;
        if ( scroll > 0 ) {
            document.getElementById("scroll-to-top").style.display = 'block';
        } else {
            document.getElementById("scroll-to-top").style.display = 'none';
        }
    });

    document.getElementById("scroll-to-top").addEventListener("click", function(e) {
        window.scrollTo(500, 0);
        e.preventDefault();
    });
    //Scroll to top END
});