Allow programming parallax effects in a declarative style.
Using plain object config to describe animations.
Provide smooth scrolling and compatibility with MacOS-like inertial scrolling.

VanillaJS powered; does not depend on any JavaScript libraries.

In gh-pages branch you can find example of use config files and simple realtime editor.

Internet Explorer 9+
Safari 5.1.4+
Opera 12+ (probably 11.60+)
Firefox 4+
Chrome 7+

In older browsers try to use ES5 polyfills.

parallax = new Parallax({
    cfg             : {Object},
    auto            : {boolean},
    root            : {window|HTMLElement},
    beforeRender    : {Function},
    afterRender     : {Function},
    onElementCreate : {Function},
    onElementShow   : {Function},
    onWindowResize  : {Function}
});

cfg - object containing information about how animation and positions of html element correlate to scrolling progress.

auto - set true to autostart parallax.

root - describe root element for parallax's DOM tree. Currently supports only window as root element.

beforeRender and afterRender - functions calls every time parallax core want to render something.
Callback arguments:
progress {number} current scroll progress
speed {number} current scrolling speed

onElementCreate - calls on creating of element, once for element.
Callback arguments:
element {Parallax.Element} created element, contains its DOM at 'html' property
progress {number} current scroll progress

onElementShow - calls every time on showing of element (when 'display' switched from 'none' to something truthy).
Callback arguments:
element {Parallax.Element} created element, contains its DOM at 'html' property
progress {number} current scroll progress

parallax.setProgress({number})

manually set progress.

parallax.start()

use this if you set autostart to false.

parallax.stop()

stops the parallax reflows and rendering.

Feel free to use under MIT license.