device.uuid
Get the device's Universally Unique Identifier (UUID).
var string = device.uuid;
Description
The details of how a UUID is generated are determined by the device manufacturer and specific to the device's platform or model.
Supported Platforms
- Android
 - BlackBerry WebWorks (OS 5.0 and higher)
 - iPhone
 - Windows Phone 7 ( Mango )
 - Bada 1.2 & 2.x
 - webOS
 
Quick Example
// Android: Returns a random 64-bit integer (as a string, again!)
//          The integer is generated on the device's first boot
//
// BlackBerry: Returns the PIN number of the device
//             This is a nine-digit unique integer (as a string, though!)
//
// iPhone: (Paraphrased from the UIDevice Class documentation)
//         Returns a string of hash values created from multiple hardware identifies.
//         It is guaranteed to be unique for every device and cannot be tied
//         to the user account.
// Windows Phone 7 : Returns a hash of device+current user, 
// if the user is not defined, a guid is generated and will persist until the app is uninstalled
// 
// webOS: returns the device NDUID
var deviceID = device.uuid;
Full Example
<!DOCTYPE html>
<html>
  <head>
    <title>Device Properties Example</title>
    <script type="text/javascript" charset="utf-8" src="cordova-1.8.1.js"></script>
    <script type="text/javascript" charset="utf-8">
    // Wait for Cordova to load
    //
    document.addEventListener("deviceready", onDeviceReady, false);
    // Cordova is ready
    //
    function onDeviceReady() {
        var element = document.getElementById('deviceProperties');
        element.innerHTML = 'Device Name: '     + device.name     + '<br />' + 
                            'Device Cordova: '  + device.cordova  + '<br />' + 
                            'Device Platform: ' + device.platform + '<br />' + 
                            'Device UUID: '     + device.uuid     + '<br />' + 
                            'Device Version: '  + device.version  + '<br />';
    }
    </script>
  </head>
  <body>
    <p id="deviceProperties">Loading device properties...</p>
  </body>
</html>
iOS Quirk
The uuid for iOS is not unique for a device, but is unique per application per install. This will change if you delete the app and re-install, and possibly also when you upgrade your iOS version, or even upgrade your app per version (as we've seen in iOS 5.1). Not a reliable value.
Windows Phone 7 Quirks
The uuid for Windows Phone 7 requires the permission ID_CAP_IDENTITY_DEVICE. Microsoft will likely be deprecating this property in the near future. If the capability is not available, the application generates a persistent guid, that will be maintained for the install-lifetime of the application on the device.