/**
 * Select a random element from array
 */
Array.prototype.rand = function ()
{
  return this[Math.floor(Math.random() * 0x40000000) % this.length];
};

/**
 * Verify if the value is null
 *
 * @param value
 * @return boolean
 */
Object.isNull = function (value)
{
  return value == null;
};