Scrolly

Live example: http://lab.victorcoulon.fr/javascript/scrolly/ (inspired by Nike Better World)

HTML

<div id="item" class="parallax" data-velocity=".8"></div> 

You can add data-fit="xx" to adjust your parallax in real conditions.

If it's a simple element, like an image.

$('.parallax').scrolly(); 

If not:

$('.parallax').scrolly({bgParallax: true}); 

######License MIT Licence