gistfile1.js

/**
 * Get random charactor from a given charset
 */

var getRandomChar = (function(str) {
  var len = str.length;
  
  return function() {
    return str.charAt(Math.floor(Math.random() * len));
  };
}(String.fromCharCode.apply(null, (function() {
  var buffer = [], start = 12449, limit = 12531;

  while (
    (start < limit) && buffer.push(start++)
  );
  
  return buffer;
}()))));