Enable TeX support on vk

vk-tex.user.js

// ==UserScript==
// @author         Petr Kalinin
// @name           Support MathJax in vk.com
// @version        0.2
// @date           2012-09-25
// @description    Load MathJax code to vk.com pages
// @license        MIT (https://opensource.org/licenses/MIT)
// @include        http://vk.com/*
// @include        http://*vk.com/*
// @include        https://vk.com/*
// @include        https://*vk.com/*
// ==/UserScript==

/*
    UserScript to convert (La)TeX on vk.com pages to images via MathJax
    Copyright (C) Petr Kalinin, 2012

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

if (window.location.href.indexOf('vk.com')>-1)
{ 
  var head = document.getElementsByTagName("head")[0], script;
  script = document.createElement("script");
  script.type = "text/x-mathjax-config";
  script[(window.opera ? "innerHTML" : "text")] =
    "MathJax.Hub.Config({\n" +
    "  tex2jax: { \n" +
    "    inlineMath: [['\\\\(','\\\\)']],\n" +
    "    displayMath: [['\\\\[','\\\\]']],\n" +
    '    skipTags: ["script","noscript","style","textarea","pre","code"]\n' +
    " }\n" +
    "});"
  head.appendChild(script);
  script = document.createElement("script");
  script.type = "text/javascript";
  script.src  = "http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML";
  head.appendChild(script);
  
  var willRunMathJax = 0;
  setInterval( function() { willRunMathJax = 0; } , 2000);

  function queueTypeset() { 
         MathJax.Hub.Queue(function () {
            willRunMathJax = 0;
         });         
         MathJax.Hub.Queue(["Typeset",MathJax.Hub]); 
  }
  
  function processDocumentChange() {
      if (willRunMathJax== 0) {
         willRunMathJax = 1;
         setTimeout(queueTypeset, 2000);
      }
  }

  var body = document.getElementsByTagName("body")[0];
  // Not sure we need to trigger all these events, by why not?
  body.addEventListener('DOMNodeInserted', processDocumentChange, false );
  body.addEventListener('DOMNodeInsertedIntoDocument', processDocumentChange, false );
  body.addEventListener('DOMCharacterDataModified', processDocumentChange, false );
}