text: function solve() {
      let parent = document.getElementById('exercise').children;
      let encodeSent = parent[0];
      let decodeRead = parent[1];
  
      let encodeSentButton = encodeSent.getElementsByTagName('button')[0];
      encodeSentButton.addEventListener('click', encodeAndSent);
  
      let decodeReadButton = decodeRead.getElementsByTagName('button')[0];
      decodeReadButton.addEventListener('click', decodeAndRead);
  
      console.log(encodeSent);
      console.log(decodeRead);
  
      function encodeAndSent(e) {
          let encodeTextArea = encodeSent.getElementsByTagName('textarea')[0].value;
          let encodedText = '';
          for (let i = 0; i < encodeTextArea.length; i++) {
              encodedText += nextChar(encodeTextArea[i]);
          }
  
          encodeSent.getElementsByTagName('textarea')[0].value = '';
          decodeRead.getElementsByTagName('textarea')[0].value = encodedText;
  
          function nextChar(c) {
              return String.fromCharCode(c.charCodeAt(0) + 1);
          }
      }
  
      function decodeAndRead(e) {
          let decodeTextArea = decodeRead.getElementsByTagName('textarea')[0].value;
          let decodedText = '';
          for (let i = 0; i < decodeTextArea.length; i++) {
              decodedText += previousChar(decodeTextArea[i]);
          }
  
          decodeRead.getElementsByTagName('textarea')[0].value = decodedText;
  
          function previousChar(c) {
              return String.fromCharCode(c.charCodeAt(0) - 1);
          }
      }
  }function solve() {
      let parent = document.getElementById('exercise').children;
      let encodeSent = parent[0];
      let decodeRead = parent[1];
  
      let encodeSentButton = encodeSent.getElementsByTagName('button')[0];
      encodeSentButton.addEventListener('click', encodeAndSent);
  
      let decodeReadButton = decodeRead.getElementsByTagName('button')[0];
      decodeReadButton.addEventListener('click', decodeAndRead);
  
      console.log(encodeSent);
      console.log(decodeRead);
  
      function encodeAndSent(e) {
          let encodeTextArea = encodeSent.getElementsByTagName('textarea')[0].value;
          let encodedText = '';
          for (let i = 0; i < encodeTextArea.length; i++) {
              encodedText += nextChar(encodeTextArea[i]);
          }
  
          encodeSent.getElementsByTagName('textarea')[0].value = '';
          decodeRead.getElementsByTagName('textarea')[0].value = encodedText;
  
          function nextChar(c) {
              return String.fromCharCode(c.charCodeAt(0) + 1);
          }
      }
  
      function decodeAndRead(e) {
          let decodeTextArea = decodeRead.getElementsByTagName('textarea')[0].value;
          let decodedText = '';
          for (let i = 0; i < decodeTextArea.length; i++) {
              decodedText += previousChar(decodeTextArea[i]);
          }
  
          decodeRead.getElementsByTagName('textarea')[0].value = decodedText;
  
          function previousChar(c) {
              return String.fromCharCode(c.charCodeAt(0) - 1);
          }
      }
  }