chips-ahoy.js

var input = '49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d';
var result = 'SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t';

function hexToPT(hex) {
  var str = '';
  
  for (var i = 0; i < hex.length; i += 2) {
    str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
  }
  
  return str;
}

var converted = window.btoa(hexToPT(input));

console.log(converted === result);