Board Thread:Wikia Discussion/@comment-26091666-20160125084257/@comment-26154973-20160217215131

I'd prefer JS because of local storage, the choice can be remembered and work across all pages and browser sessions.

MediaWiki:DropList.js (to include in MediaWiki:Common.js):

(function($) {   "use strict";    console.log("Template:DropList helpers v1");    var localStorageProperty = "droplist_showNonRare";    $(document).ready(function { if(typeof(Storage) === "undefined") { return; }       function show { localStorage[localStorageProperty] = "1"; $(".droplist-non-rare-ship").show; $(".droplist-checkbox-icon").text("☑"); }       function hide { localStorage[localStorageProperty] = "0"; $(".droplist-non-rare-ship").hide; $(".droplist-checkbox-icon").text("☒"); }       if (!localStorage[localStorageProperty] || localStorage[localStorageProperty] === "1") { show; } else { // localStorage[localStorageProperty] === "0" hide; }       $(".droplist-checkbox").click(function {            if (localStorage[localStorageProperty] === "1") {                hide;            } else { // localStorage[localStorageProperty] === "0"                show;            }        }); }); }(jQuery));

and there is a button in Template:DropList/doc.