//Get the user input
    const getValue = () => {
      //hide the alert
      document.getElementById('alert').classList.add('invisible');
      //get userString from the page
      let userString = document.getElementById('userString').value;
    
      //check for palindrome
      let returnObj = checkForPalindrome(userString);
    
      //display out message to the screen
      displayMessage(returnObj);
    };
    //check if string is a palindrome
    const checkForPalindrome = (userString) => {
      //transform all upper case letters to lowercase
      userString = userString.toLowerCase();
    
      //remove spaces and special characters
      let regex = /[^a-z0-9]/gi;
      userString = userString.replace(regex, '');
    
      let revString = [];
      let returnObj = {};
    
      for (let index = userString.length - 1; index >= 0; index--) {
        revString += userString[index];
      }
    
      if (revString == userString) {
        returnObj.msg = 'Well done! You entered a palindrome!';
      } else {
        returnObj.msg = 'Sorry! You did not enter a palindrome.';
      }
    
      returnObj.reversed = revString;
    
      return returnObj;
    };
    
    //Display the message back to the user
    const displayMessage = (returnObj) => {
      //write to the page
      document.getElementById('alertHeader').innerHTML = returnObj.msg;
      document.getElementById(
        'msg'
      ).innerHTML = `Your phrase reversed is: ${returnObj.reversed}`;
      //show the alert box
      document.getElementById('alert').classList.remove('invisible');
    };
              
                
            

Hello World