Removes the @user joined the #channel and @user left the #Channel messages on slack.
// ==UserScript==
// @name Remove Joined and Left messages on Slack
// @namespace http://tampermonkey.net/
// @version 0.1
// @description Removes the @user joined the #channel and @user left the #Channel messages on slack.
// @author Jaswant R
// @include *.slack.com*
// @grant none
// ==/UserScript==
(function() {
'use strict';
setInterval(function(){ $('.message.joined').hide(); }, 1000);
// Your code here...
})();