$(document).ready(function() {
    
    $('div[data-type="background"]').each(function(){
        var $bgobj = $(this);
        
        $(window).scroll(function() {
            var yPos = -($(window).scrollTop() / $bgobj.data('speed'));
            var coords = ($bgobj.data("origin") + yPos) + 'px';
            $bgobj.css({ top: coords });
        });
    });
    
});