openvk/Web/static/js/scroll.js

window.addEventListener("scroll", function(e) {
    if(window.scrollY < 100) {
        if(window.temp_y_scroll) {
            u('.toTop').addClass('has_down')
        }
        document.body.classList.toggle("scrolled", false);
    } else {
        document.body.classList.toggle("scrolled", true);
        u('.toTop').removeClass('has_down')
    }
});

u(".toTop").on("click", function(e) {
    const y_scroll = window.scrollY
    const scroll_margin = 20

    if(y_scroll > 100) {
        window.temp_y_scroll = y_scroll
        window.scrollTo(0, scroll_margin)
        window.scrollTo({
            top: 0,
            behavior: "smooth"
        })
    } else {
        if(window.temp_y_scroll) {
            window.scrollTo(0, window.temp_y_scroll - scroll_margin)
            window.scrollTo({
                top: window.temp_y_scroll,
                behavior: "smooth"
            })
        }
    }

    u(document).trigger('scroll')
})