Parallax

landing.js

    function parallax(element) {

        var offset = 1;

        // Determine whether scrolling up or scrolling down
        var st = $(this).scrollTop();
        if (st < lastScrollTop){
            offset = offset * -1;
        }
        lastScrollTop = st;

        var pos = element.css('background-position').split(" ");
        pos[0] = parseInt(pos[0].replace("%","").replace("px",""));
        pos[1] = parseInt(pos[1].replace("%","").replace("px","")) - offset;
        newpos = pos[0] + 'px ' + pos[1] + 'px';
        $('#opacityMask').css('background-position', newpos)
    }