MPGH Codeblocks Syntax Highlight

// ==UserScript==
// @name MPGH Code Blocks Syntax Highlight  
// @author Mike Rohosft
// @grant       GM.setValue
// @grant       GM.getValue
// @include https://www.mpgh.net/forum/*
// ==/UserScript==
  
function responseHandler(text) {
    GM.setValue('prettyprint', text);
    const b = new Blob([text], { type: 'text/javascript' });
    const u = URL.createObjectURL(b);
    const script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = u;
    document.head.appendChild(script);
}
  
window.addEventListener('load', function init() {
    const code_blocks = document.getElementsByClassName("bbcode_code");
    for (let i = 0, v; v = code_blocks[i]; i++) {
    	if (v.tagName.toLowerCase() !== 'pre') {
		    continue;
        }
        v.classList.add('prettyprint');  
    }
    GM.getValue('prettyprint').then(textblob => {
			if (!textblob) {
      	fetch('https://cdn.jsdelivr.net/gh/google/code-prettify@master/loader/run_prettify.js').then(res => res.text().then(responseHandler));  
      } else {
        responseHandler(textblob); 
      }
    });
    window.removeEventListener('load', init);
});