Easy parallax scroll effect

parallax-scroll.js

// https://bolt.cm/

// MAKE TOPIMAGE SCROLL SLOWER FOR PARALLAX EFFECT
$(window).scroll(function () {
    $('header').css('backgroundPosition', '0px ' + (posTop() / 2) + 'px');
});

// FIX FOR SCROLLPOS IN ALL BROWSERS
function posTop() {
    return typeof window.pageYOffset != 'undefined' ? window.pageYOffset: document.documentElement.scrollTop? document.documentElement.scrollTop: document.body.scrollTop? document.body.scrollTop:0;
}