Twitter - NG Word Filter for Greasemonkey http://userscripts-mirror.org/scripts/show/94957

Twitter_-_NG_Word_Filter_Mod.user.js

// ==UserScript==
// @name           Twitter - NG Word Filter Mod
// @namespace      http://d.hatena.ne.jp/Cherenkov/
// @description    Hide NG word
// @version        0.3
// @date           20150911
// @include        http://twitter.com/*
// @include        https://twitter.com/*
// @grant          GM_addStyle
// @grant          GM_registerMenuCommand
// ==/UserScript==

(function(){
  // NG word (RegExp)：
  var ngwords = /#4ji|#followme|I'm at/i;

  // user name：
  // GM_addStyle('.tweet[data-name="USER_NAME1"], .tweet[data-name="USER_NAME2"] {display:none !important;}');


  GM_addStyle('._GM_wordFilter { display: none !important; border: 3px dashed red; }');
  // GM_addStyle('._GM_wordFilter { background-color:pink !important; border: 3px dashed red; }'); //debug
  var wordFilter = function (elem) {
    var tweet = elem.querySelector('.js-tweet-text');
    if(!tweet) return;
    var text = tweet.textContent;
    if (ngwords.test(text)) {
      elem.classList.add('_GM_wordFilter');
    }
  }
  function init() {
    Array.prototype.forEach.call(document.querySelectorAll('.stream-item'), function(elem) {
      wordFilter(elem);
    });
  }
  init();

  var observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
      for (var i = 0, len = mutation.addedNodes.length; i < len; i++) {
        var elem = mutation.addedNodes[i];
        if (elem.id && elem.id.indexOf('stream-item-tweet') !== -1) {
          wordFilter(elem);
        }
      }
    });
  });
  observer.observe(document.getElementById('stream-items-id'), { childList: true });

  GM_addStyle('._GM_wordFilterMark { display: block !important; }');
  GM_registerMenuCommand("Twitter - NG Word Filter > visible", function() {
    Array.prototype.forEach.call(document.querySelectorAll('._GM_wordFilter'), function(elem) {
      elem.classList.add('_GM_wordFilterMark');
    });
  });
})();