//controller function
function getValue() {

  let inputWordRaw = document.getElementById("wordHTML").value.toLowerCase();
  let inputWord = inputWordRaw.replace(/[^a-zA-Z0-9]/gi, "");

  let palCheck = palindromeCheck(inputWord);
  displayCheck(palCheck);
}


function palindromeCheck(message) {
  //string = array of characters
  let reversedMessage = "";

  for (let i = message.length - 1; i >= 0; i--) {
    reversedMessage += message[i];
  }
  if (reversedMessage == message) {
    Swal.fire({
      backdrop: false,
      title: "Yep,",
      text: "That's a palindrome!",
    });
  } else {
    Swal.fire({
      backdrop: false,
      title: "Nope",
      text: "That is not a palindrome",
    });
  }
}
JavaScript

The code is structured in two functions:

getValue()

Collects a string that the user has input.

palindromeCheck()

uses a "for" loop to reverse the message, then checks if the reversed message matches the original message. It then displays the answer with a Sweet Alert.