Programming Puzzles and Code Golf character counter for answers

gistfile1.js

/* stolen from http://stackoverflow.com/a/5515960/390819 */
function lengthInUtf8Bytes(str) {
  /* Matches only the 10.. bytes that are non-initial characters in a multi-byte sequence. */
  var m = encodeURIComponent(str).match(/%[89ABab]/g);
  return str.length + (m ? m.length : 0);
}

var answers = document.querySelectorAll('div.answer');

var codeBoxes = Array.prototype.map.call(answers, function(a){
    return a.querySelector('pre'); 
}).filter(function (x) { return x; });

codeBoxes.forEach(function(c){
    var length = lengthInUtf8Bytes(c.textContent.replace(/\n*$/, ''));
    var countDiv = document.createElement('div');
    countDiv.style.color = 'rgb(239, 110, 31)';
    countDiv.innerHTML = 'Byte count: <strong>' + length + '</strong>';

    c.parentNode.insertBefore(countDiv, c);
});