relSignalStrength is a read-only property that gives the signal strength, represented linearly as a number.
var dataSignal = navigator.mozMobileConnection.data.relSignalStrength; var voiceSignal = navigator.mozMobileConnection.voice.relSignalStrength;
Return a number between 0 (weakest signal) and 100 (full signal).
This property can be
null if there is no signal at all.
Not part of any specification.