title: Get Unique device id with php or javascript
body: <p>I'm looking for something that allow me to get devices (pc, Mac, phone and tablet) unique id like a MAC address can be.</p>
  
  <p>I need to track all logins into a protected area but i'm unable to find an unique id with whom I can identify the used device.</p>
  
  <p>I need that because I want the user to register their devices and then let them login only with that. Thanks</p>