The sendTones() method of the Telephony Interface generates multiple DTMF tones, with a specified duration for each tone, and an optional delay before generation starts. The tones are sent to the currently active call.
The startTone() method of the Telephony Interface begins generating the tone for the specified DTMF character. The tone is sent to the currently active call, and continues to sound until a corresponding call to Telephony.stopTone().
The VRDisplay interface of the WebVR API represents any VR device supported by this API. It includes generic information such as device IDs and descriptions, as well as methods for starting to present a VR scene, retrieving eye parameters and display capabilities, and other important functionality.
The displayId read-only property of the VRDisplay interface returns an identifier for this particular VRDisplay, which is also used as an association point in the Gamepad API (see Gamepad.displayId).