Responsive Background Image Delivery Using Vanilla JavaScript
bg-responsive.js is a vanilla JavaScript library that allows to intelligently load the appropriate background images based on the screen size you’re viewing on.
JavaScript & CSS background
Animated Gradient Background with Pure CSS
An animated gradient background using CSS3 box-shadow property and keyframe animations, written in LESS and created by blucube.
Javascript Plugin For Adaptive Image Background Color – Adaptive Backgrounds
Adaptive Backgrounds is a standalone javascript plugin combined with RGBaster.js that allows to extract the dominant color from an image and apply it to the background of its parent element.