I'm a user-friendlier drop-in replacement for the standard <select> with multiple attribute activated. Free (under MIT license) Works in an unobtrusive fashion Fully open sourced Keyboard support Provides some callbacks Fully customizable via CSS Depends on jQuery 1.8+ Tiny code ~8kb minified gem for Rails HTML <html> <head> <link href="path/to/select-multiple.css" media="screen" rel="stylesheet"