JavaScript Program To Check Whether a String is Palindrome or Not.

Problem: Write a function to check if a given string is a palindrome. A palindrome string is a sequence of characters that reads the same backward as forward. In other words, a string is a palindrome if reversing the string gives the same string.

Examples of Palindrome Strings.

• “radar”
• “level”
• “madam”
• “racecar”
• “A man, a plan, a canal, Pan

Approach 1:

function isPalindrome(str){
  return (str.toLowerCase().split('').reverse().join('') == str.toLowerCase()) ? 'Palindrome String':'Not a Palindrome String' ;
}

console.log(isPalindrome('racecar')); 

Output: Palindrome String

console.log('JavaScript'); 

Output: Not a Palindrome String

console.log(isPalindrome('racecar'));

Ouput: Palindrome String

Approach 2:

function isPalindrome(str){
    let revstring = '';
    for(let i=str.length-1;i>=0;i--){
        revstring+=str[i];
    }
    return (revstring.toLowerCase() == str.toLowerCase()? 'Palindrome String':'Not a Palindrome String');
}

console.log(isPalindrome('racecar'));

Output: Palindrome String

console.log(isPalindrome('JavaScript'));

Output: Not a Palindrome String

console.log(isPalindrome('racEcaR'));

Palindrome String