Javascript String isPalindrome()

//EX1//from   w  w w. j av a2 s  .  com
String.prototype.isPalindrome=function(){
  var palavra=this;
  for(var i=0;i<palavra.length/2;i++){
    if(palavra[i]!=palavra[palavra.length-1-i]){
      return false;
    }
  }
  return true;
}
//EX2
Date.prototype.bissexto=function(){
  var ano=this.getFullYear();
  if(ano % 4 === 0 && (ano % 100 != 0) || (ano % 400 === 0)){
    return true;
  }
  return false;
}

String.prototype.isPalindrome = ()=>{
  return this.replace(/[^a-zA-Z ]/g, "").replace(/ /g,'').trim().toLowerCase() == this.replace(/[^a-zA-Z ]/g, "").replace(/ /g,'').trim().toLowerCase().split('').reverse().join('');
}

String.prototype.isPalindrome = function() {
  var str = this;
  var half = parseInt(str.length / 2, 10);

  for (var i = 0, last = str.length - 1; i < half; ++i) {
    if (str[i] != str[last - i]) return false;
  }/* www.  j a  va 2  s . c o  m*/

  return true;
};

/* return if a string is a palindrome */
String.prototype.isPalindrome = function() {
    var str = this.replace(/\W/g, '');
    return str.toLowerCase() === str.toLowerCase().split('').reverse().join('');
};

var isPal = 'a man a plan a canal panama'.isPalindrome();
console.log(isPal); //true

// Monkeypatching is the act of adding functionality onto an object that
// wouldn't ordinarily be there, or to override existing functionality.

String.prototype.isPalindrome = function() {
 var val = this.toString().toLowerCase();
 var reverse = val.split('').reverse().join('');
 return val === reverse;
}

var str = 'something';
var result = str.isPalindrome(); // false

var str2 = 'level';
var result2 = str2.isPalindrome(); // true

'use strict'//from   w  w w  .j  a va 2s . c  o m

function isPalindrome(str) {
    var replStr = str.replace(/[.,"'\/#!$%\^&\*;:{}=\-_`~()\s]/g, "").toLowerCase();
    var revStr = replStr.split('').reverse().join('');
    //console.log(replStr);
    //console.log(revStr);
    if (replStr === revStr) {
        return true;
        } else {
            return false;
        }
    };
        
String.prototype.isPalindrome = String.prototype.isPalindrome || isPalindrome;

// 004 Find the largest palindromic product of two three-digit numbers

var first = 999,//from w ww.  j a va  2  s . c  o m
    second = 999,
    largestPalindromicProduct = 0;

String.prototype.isPalindrome = function() {
 return this == this.reverse();
}

String.prototype.reverse = function() {
 return this.split("").reverse().join("");
};

while(first > 99) {
 second = first;
 while(second > 99) {
  var product = first * second;
  if(product.toString(10).isPalindrome() && product > largestPalindromicProduct)
   largestPalindromicProduct = product;
  second--;
 }
 first--;
}

console.log(largestPalindromicProduct);

String.prototype.isPalindrome = function () {
  // Note that a primitive JavaScript string is not === to a String object.
  // The valueOf function returns the underlying primitive.
  return this.valueOf() === this.reverse().valueOf();
};
String.prototype.reverse = function () {
  return Array.prototype.slice.apply(this).reverse().join('');
};

let result = 0;//from ww w .j a va 2s .c  o m
for (let i = 999; i > 0; i--) {
  for (let j = i; j > 0; j--) {
    let x = i * j;
    if (x.toString().isPalindrome() && x > result)
      result = x;
  }
}
print(result);

String.prototype.isPalindrome = function () {
    var s = this.toLowerCase().replace(/[^a-z]/g, '');
    return (s.reverse() === s);
};
String.prototype.reverse = function () {
    return this.split('').reverse().join('');
};

var isPalindrome = function(str){
  var i = 0;/*  w  w w  .j  ava  2 s . c o  m*/
  var j = str.length-1;
  while (i <= j){
    if (str[i] != str[j]){
      return false;
    }
    i++;
    j--;
  }
  return true;
}

var isPalindrome2 = function(string){
  for (var i = 0, j = string.length-1; i < string.length/2; i++, j--){
    if (string[i] != string[j]){
      return false;
    }
  }
  return true;
}

String.prototype.isPalindrome = function(){
  // return isPalindrome(this);
  var i = 0;
  var j = this.length-1;
  while (i <= j){
    if (this[i] != this[j]){
      return false;
    }
    i++;
    j--;
  }
  return true;
}

//Scooter's Solution

var isPalindrome = function(inString) {
 var inString = inString.toLowerCase();
   //(var i = 0; i < string.length/2; i++)
 for (var i = 0, j = inString.length-1; i < inString.length/2; i++, j--) {
  //if (string[i] !== string[string.length-(i+1)] )
  if (inString[i] != inString[j]){
   return false;// w w w .ja  va 2s  .com
  }
 }
 return true;
}

//Chucks Solution

String.prototype.isPalindrome = function isPalindrome() {
 console.log(this);
 var new_str = this.toString().replace(" ", "");
 if (new_str == new_str.split("").reverse().join("")) {
  return true;
 } else {
  return false;
 }
}

// Example - extending a method in String

String.prototype.isPalindrome = function() {
 return this.replace(/[^A-Z0-9]/ig, "").toLowerCase() === this.split("").reverse().join("");
};

console.log("madam".isPalindrome()); // true
console.log("str".isPalindrome()); // false