zdoc/layouts/partials/script/codeblock-script.html

<script>
  'use strict';
  // ====================== markdown code block ======================
  function wrap(el, wrapper) {
    el.parentNode.insertBefore(wrapper, el);
    wrapper.appendChild(el);
  }

  (function () {
    var singleContentsElem = document.querySelector('.single__contents');
    singleContentsElem ? 
    singleContentsElem.querySelectorAll('pre > code').forEach(function(elem) {
      var dataLang = elem.getAttribute('data-lang');
      var dataLangWrapper = document.createElement('div');
      var code = null;
      var codeTitle = null;

      if (dataLang && dataLang.includes(':')) {
        code = dataLang.split(':')[0];
        codeTitle = dataLang.split(':')[1];

        dataLangWrapper.className = 'language-' + code;
        dataLangWrapper.setAttribute('data-lang', codeTitle);

        elem.className = 'language-' + code;
        elem.setAttribute('data-lang', codeTitle);
        elem.setAttribute('id', codeTitle);
      }

      if (!dataLang || codeTitle) {
        wrap(elem.parentNode, dataLangWrapper);
      }

    }) : null;
  })();
  // =================================================================
</script>