Generates a unique fingerprint in javascript alone.

gen_fingerprint.coffee

gen_fingerprint = ->
  # in reference to: http://stackoverflow.com/questions/105034/create-guid-uuid-in-javascript
  'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace /[xy]/g, (c) ->
    r = Math.random() * 16 | 0
    v = if c == 'x' then r else r & 0x3 | 0x8
    v.toString 16

gen_fingerprint.js

var gen_fingerprint = function(){ // in reference to: http://stackoverflow.com/questions/105034/create-guid-uuid-in-javascript
  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);}));
}