how to do palindrome in javascript code example

Example 1: palindrome in javascript

function palindrome(str) {

    var len = str.length;
    var mid = Math.floor(len/2);

    for ( var i = 0; i < mid; i++ ) {
        if (str[i] !== str[len - 1 - i]) {
            return false;
        }
    }

    return true;
}

Example 2: javascript palindrome check

function palindrome(str) {
  var re = /[\W_]/g;
  var lowRegStr = str.toLowerCase().replace(re, '');
  var reverseStr = lowRegStr.split('').reverse().join(''); 
  return reverseStr === lowRegStr;
}
palindrome("A man, a plan, a canal. Panama");

Example 3: palindrome javascript

function palindrome(str) {
 var splitted = str.split("");
 var reversed = splitted.reverse("");
 var joined = reversed.join("");
 return joined.toLowerCase().replace(/[^0-9a-z]/gi, '') == str.toLowerCase().replace(/[^0-9a-z]/gi, '')
}

Example 4: javascript palindrome check

function palindrome(str) {
 var re = /[^A-Za-z0-9]/g;
 str = str.toLowerCase().replace(re, '');
 var len = str.length;
 for (var i = 0; i < len/2; i++) {
   if (str[i] !== str[len - 1 - i]) {
       return false;
   }
 }
 return true;
}
palindrome("A man, a plan, a canal. Panama");