This article is in need of a technical review.
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
onussdreceived property specifies an event listener to receive
ussdreceived events. These events occur whenever a new USSD message is received.
navigator.mozMobileConnection.onussdreceived = funcRef;
funcRef is a function to be called when the
ussdreceived event occurs.
Not part of any specification.