Parallax, like stamfordglobal.com

parallax.js

(function ($) {
  Drupal.behaviors.parallaxScrolling = {
    attach: function (context) {

      $('[data-type]').each(function() {
        $(this).data('offsetY', parseInt($(this).attr('data-offsetY')));
        $(this).data('speed', $(this).attr('data-speed'));
      });

      $('div[data-type="background"]').each(function() {
        var $self = $(this),
            offsetCoords = $self.offset(),
            topOffset = offsetCoords.top,
            $window = $(window);
        
        if ($(window).width() >= 800) {
          $(window).scroll(function() {
            if ( ($window.scrollTop() + $window.height()) > (topOffset) && ( (topOffset + $self.height()) > $window.scrollTop() ) ) {
              var yPos = ((topOffset-$window.scrollTop()) / $self.data('speed'));
              if ($self.data('offsetY')) {
                yPos += $self.data('offsetY');
              }

              var coords = '50% '+ yPos + 'px';
              $self.css({ backgroundPosition: coords });
            };
          });
        }
      });
    }
  };
})(jQuery);