google tag manager (gtm) userscript for tampermokey

gtm-userscript.js

// ==UserScript==
// @name      Google Tag Manager Test Script
// @namespace  http://www.tikodigital.com/
// @version    0.1
// @description  Code to Run Google Tag Manager Client Side 
// @include      *domain.com*
// @copyright  2014 Tiko Digital
// ==/UserScript==

var actualCode = '(' + function() {
    // All code is executed in a local scope.
    // To overwrite a global variable, prefix `window`:

(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXX');
 
} + ')();';
 
var script = document.createElement('script');
script.textContent = actualCode;
(document.head||document.documentElement).appendChild(script);
script.parentNode.removeChild(script);