[support] Finding device id or mobile phone number

[Scott]

In regards to my Citysearch API module, tracking clicks from mobile
devices requires that a device id or phone number be included in the
javascript arguments.  I don't know where to find this information.  My
mobile phone has been borrowed for the day so I can only emulate on
firefox.  I've looked through the output of phpinfo() and
$requestingDevice->getAllCapabilities(); but can find nothing that looks
appropriate.  I suspect that the wurfl API contains a function I'm
unaware of. My google searches have so far come up empty.