To initialize the plugin, call the parallaxScroll method on your background elements.
The plugin accepts one option – friction. It should be a float value that is more than 0 and less than 1. 0 causes the background to behave as it has background-attachment: scroll (which is useless). 1 (maximum friction) is the same as background-attachment: fixed. A value greater than 1 will cause the background to scroll in reverse!
Other features available in Pederan’s plugin such as holderMinHeight and coverRatio can be achieved purely with CSS and should be. The fallback option to turn off parallax in mobile devices is unnecessary because this plugin works smoothly on mobile devices.