Nimbus.js

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/* Any JavaScript here will be loaded for users using the Nimbus skin */

/* Random logo */
var logos = [
/* Halo 5 */
'/images/0/02/Logo_John.png', '/images/6/6a/Logo_Fred.png', '/images/d/d8/Logo_Kelly.png', '/images/4/47/Logo_Linda.png', '/images/b/bd/Logo_Locke.png', '/images/c/ce/Logo_Buck.png', '/images/f/f4/Logo_Tanaka.png', '/images/b/bb/Logo_Vale.png', '/images/c/c0/Halopedia_Logo_Palmer.png', '/images/9/99/Halopedia_Logo_Roland.png',

/* Halo 3 */
'/images/b/bd/Halopedia-Logo-Spark.png', '/images/4/4d/Halopedia-Logo-Thel.png', '/images/b/bb/Halopedia_Logo_Miranda.png', 

/* Halo 3: ODST */
'/images/9/93/Halopedia_Logo_Quick.png', '/images/6/6b/Halopedia_Logo_Dare.png', '/images/7/76/Halopedia_Logo_Dutch.png', '/images/2/27/Halopedia_Logo_Mickey.png', '/images/8/8b/Halopedia_Logo_Romeo.png', '/images/7/7a/Halopedia_Logo_Rookie.png',

/* Halo Wars */
'/images/a/a2/Halopedia-Logo-Jerome.png', '/images/5/5f/Halopedia-Logo-Johnson.png', '/images/c/ce/Halopedia-Logo-Anders.png', '/images/5/5f/Halopedia-Logo-Atriox.png', '/images/4/40/Halopedia-Logo-Cutter.png', '/images/3/39/Halopedia-Logo-Forge.png', '/images/3/33/Halopedia_Logo_Serina.png', '/images/0/0d/Halopedia_Logo_Ripa.png',

/* Books */
'/images/3/3c/Halopedia-Logo-Veta.png', '/images/5/5b/Halopedia-Logo-Tem.png', '/images/2/26/Halopedia-Logo-Olivia.png', '/images/7/77/Halopedia_Logo_GrayTeam.png', '/images/e/eb/Halopedia_Logo_Jul.png', '/images/5/5a/Halopedia_Logo_Keyes.png',

/* Mixed Media */
'/images/a/a8/Halopedia-Logo-Lasky.png', '/images/8/87/Halopedia-Logo-Halsey.png', '/images/3/32/Halopedia-Logo-Rtas.png', '/images/a/a3/Halopedia_Logo_Hood.png', '/images/e/eb/Halopedia_Logo_Mendez.png', '/images/0/00/Halopedia_Logo_Cortana.png',
'/images/0/0a/Halopedia_Logo_Faber.png', '/images/0/0c/Halopedia_Logo_Didact.png', '/images/4/45/Halopedia_Logo_Librarian.png', '/images/9/91/Halopedia_Logo_MendicantBias.png',

];
$('#site-logo a').css('background-image', 'url(' + logos[Math.floor(Math.random() * logos.length)] + ')');

MediaWiki:Nimbus.js