Heard a problem set the other day to make a function detecting if a string is a palindrome. Wanted to give it a shot.

racecar.js

'use strict';

function reverseString(input) {
  var result = "";
  for( var i = (input.length-1); i >= 0; i-- ) {
    result = result + input[i];
  }

  return result;
}

function collectToIndex(input, index) {
  var result = "";
  for( var i = 0; i < index; i++ ) {
    result += input[i];
  }

  return result;
}

function isPalindrome(input) {
  var rightSide, leftSide, collectionIndex;

  if( (input.length % 2) == 0 ) {  // If odd, set our index up one to grab proper character
    collectionIndex = (input.length / 2) + 1;
  } else {
    collectionIndex = (input.length / 2);
  }

  leftSide = collectToIndex(input, collectionIndex);
  rightSide = collectToIndex(reverseString(input), collectionIndex);

  if(leftSide == rightSide) {
    return true;
  } else {
    return false;
  }

}

console.log( isPalindrome('racecar') );   // -> true
console.log( isPalindrome('racercars') ); // -> false