rc = pre.getAttribute('data-src');
            var extension = (src.match(/\.(\w+)$/) || [, ''])[1];
            var language = 'php';

            var code = document.createElement('code');
            code.className = 'language-' + language;

            pre.textContent = '';

            code.textContent = 'Loading…';

            pre.appendChild(code);

            var xhr = new XMLHttpRequest();

            xhr.open('GET', src, true);

            xhr.onreadystatechange = function () {
             