code: function injectCode(code, id) {
    var pre = document.getElementById(id);
    pre.textContent = code;
    code = pre.innerHTML;
    code = prettyPrintOne(code, 'js');
    pre.innerHTML = code;
  }
docs: Inject code into a pre tag, with syntax highlighting.
  Safe from HTML/script injection.
  @param {string} code Lines of code.
  @param {string} id ID of <pre> element to inject into.