Create GUID

guid.js

/**
 * Creates a random guid. 
 * 
 * @example 064ca254-ab32-4a0b-bb38-4a35c730f323
 */
function guid(){
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random()*16|0, v = c === 'x' ? r : (r&0x3|0x8);
    return v.toString(16);
  });
}