This Chome userscript for the Danish site Just-eat.dk will dim most menues containing meat.

just-eat-veggie.user.js

// ==UserScript==
// @match http://*.just-eat.dk/*
// ==/UserScript==
function oc(a){
  var o={};
  for(var i=0;i<a.length;i++) {o[a[i]]=true;}
  return o;
};
var meats = oc('beef,blæksprutte,blæksprutter,bøf,bacon,chicken,crab,crabstick,grillkylling,kebab,kylling,kyllinge,kyllingelår,kød,kødsauce,kødstrimler,lam,lamb,lobster,okseburger,oksekød,pepperoni,pølse,pølser,rejer,rejecocktail,skinke,shawarma,tun,tuna,tunfisk'.split(','));


var MeatAnalyzer = (function() {
  var m = {};
  m.strToWords = function(str) {
    function slugize() {
      return str.replace(/[^a-zA-Z0-9åäæöøÅÄÆÖØ\s]/g," ").replace(/[\n\r\t]/g,' ').replace('  ', ' ').toLowerCase();
    }
    return slugize().split(' ');
  };
  m.containsMeat = function(str) {
    var strArray = m.strToWords(str);
    var truthMap = strArray.map(function(word){
      return word in meats;
    });
    return truthMap.reduce(function(a,b){return a||b;});
  };
  m.markMeat = function(e) {
    if (m.containsMeat((e.innerText))) {
      e.className += ' meat';
    }
  }
  return m;
})();

function addStyle(str) {
  var styleNode = document.createElement('style');
  var styleText = document.createTextNode(str);
  styleNode.appendChild(styleText);
  document.getElementsByTagName('head')[0].appendChild(styleNode);
}

function analyze() {
  console.log("Running veggie-just-eat!");
  var arr = [].slice.call(document.querySelectorAll('.prdDe'));
  arr.forEach(MeatAnalyzer.markMeat);
  addStyle('.meat,.meat h6{color:rgb(166,166,166);}');
}

analyze();