// Get our user input
function getValue() {
    
    // Make sure the alert is invisible
    document.getElementById("alert").classList.add("invisible");
    
    // Get user string from the page
    let userString = document.getElementById("userString").value;

    // Check for a palindrome
    let returnObj = checkForPalindrome(userString);

    // Display our message to the screen
    displayMessage(returnObj);
}

// Check if string is a palindrome
function checkForPalindrome(userString) {


    // taco cat
    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 a message to the string.
function displayMessage(returnObj) {

    document.getElementById("alertHeader").innerHTML = returnObj.msg;
    document.getElementById("msg").innerHTML = `Your phrase reversed is: ${returnObj.reversed}`;
    document.getElementById("alert").classList.remove("invisible");
}
                        
                    

Radar is a JavaScript program takes a string as input and checks wether it is the same string in reverse.

getValue()

This function gets the string from the document object model.

checkForPalindrome()

This function checks wether the string is the same in reverse. If it is a palindrome it calls the displayMessage function.

displayMessage()

This function sends the string to the document object model.