Unscrollable modal background placeholder that can be used as modal background or for mobile menu background / flying carts etc. Simply prevents scrolling when menu or some modal is opened. Contains fix for jumping content caused by removing scrollbar with mouse plugged in.

Contains darkness.css with default styling.

Works IE9+ (uses classList. with polyfill probly lower). You can use it with AMD, CommonJS, ecma6...

Simple usage shown in index.html.