 document.querySelector('#display').checked,
        latex: document.querySelector('#latex').checked,
        speech: document.querySelector('#speech').checked,
        braille: document.querySelector('#braille').checked,
        entities: document.querySelector('#entities').checked,
      });
      //
      // Set the output to the serialized MathML.
      //
      output.innerHTML = '';
      output.appendChild(document.createTextNode(mml));
      //
      // Re-enable the controls again.
      //
      I