text: function encodeAndDecodeMessages() {
      let elementToSend = document.querySelector('div#container #main:first-child textarea');
      let elementToReceive = document.querySelector('div#container #main div:last-child textarea');
      let buttonSend = document.querySelector('div#container #main:first-child button');
      let buttonReceived = document.querySelector('div#container #main div:last-child button');
      buttonSend.addEventListener('click', e => {
          let text = elementToSend.value;
          elementToSend.value = '';
          if (text && text.search(/^\s*$/)) {
              text = text.split('').map(x => String.fromCharCode(x.charCodeAt(0) + 1)).join('');
              elementToReceive.textContent = text;
          }
      });
      buttonReceived.addEventListener('click', e => {
          let text = elementToReceive.textContent;
          if (text && text.search(/^\s*$/)) {
              text = text.split('').map(x => String.fromCharCode(x.charCodeAt(0) - 1)).join('');
              elementToReceive.textContent = text;
          }
      });
  }