Check Whether a String is Palindrome or Not using JavaScript

This tutorial shows how to check whether a given string is palindrome or not using JavaScript. A string is said to be a palindrome if it is spelled the same from forward and backward. For example, “madam” is spelled the same from forward and backward. so, it is a palindrome. In JavaScript, we can use for loop or the built-in functions to check if a string is palindrome or not.

Example 1: Check Palindrome String Using for Loop

// program to check if the string is palindrome or not

function CheckPalindrome(str) {

    // find the length of a string
    const len = str.length;

    // loop through half of the string
    for (let i = 0; i < len / 2; i++) {

        // check if first and last string are same
        if (str[i] !== str[len - 1 - i]) {
            return 'It is not a palindrome';
        }
    }
    return 'It is a palindrome';
}

console.log(CheckPalindrome("madam"));
console.log(CheckPalindrome("fruit"));

Output

It is a palindrome
It is not a palindrome

Example 2: Check Palindrome String using built-in Functions

// program to check if the string is palindrome or not

function CheckPalindrome(str) {

    // reverse the string
    let reverseStr = str.split("").reverse().join("");

    if(str === reverseStr) {
        return 'It is a palindrome';
    }
    else {
        return 'It is not a palindrome';
    }
}

console.log(CheckPalindrome("madam"));
console.log(CheckPalindrome("fruit"));

Output

It is a palindrome
It is not a palindrome