parallax example from netlify

simple-parallax.js

  var parallaxImages = function parallaxImages() {
    if ($(".about.page").length && $("html.no-touchevents").length && winWidth >= 768) {
      var triggered = false
        , oldWindowPos = 0
        , fasterImgMargin = 140
        , slowerImgMargin = 40;
      $(window).on("scroll", function() {
        window.requestAnimationFrame(scrollHandler);
        function scrollHandler() {
          var currentWindowPos = $(window).scrollTop()
            , scrollingDown = currentWindowPos > oldWindowPos;
          if (scrollingDown && !triggered) {
            slowerImgMargin--;
            fasterImgMargin = fasterImgMargin - 2
          } else {
            slowerImgMargin++;
            fasterImgMargin = fasterImgMargin + 2
          }
          if (slowerImgMargin >= -169 && slowerImgMargin <= 20) {
            $("#vertical-parallax-img").css({
              transform: "translate3d(0px, " + slowerImgMargin + "px, 0px)"
            })
          }
          if (fasterImgMargin >= -278 && fasterImgMargin <= 100) {
            $("#horizontal-parallax-img").css({
              transform: "translate3d(0px, " + fasterImgMargin + "px, 0px)"
            })
          }
          oldWindowPos = currentWindowPos
        }
      })
    }
  }