SpeechSynthesisEvent

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨September 2018⁩.

TheSpeechSynthesisEvent interface of theWeb Speech API contains information about the current state ofSpeechSynthesisUtterance objects that have been processed in the speech service.

Constructor

SpeechSynthesisEvent(): Creates a newSpeechSynthesisEvent.

Instance properties

TheSpeechSynthesisEvent interface also inherits properties from its parent interface,Event.

SpeechSynthesisEvent.charIndexRead only: Returns the index position of the character in theSpeechSynthesisUtterance.text that was being spoken when the event was triggered.
SpeechSynthesisEvent.charLengthRead only: Returns the number of characters left to be spoken after thecharIndex position, if the speaking engine supports it. Returns 0 if the speaking engine can't provide the information.
SpeechSynthesisEvent.elapsedTimeRead only: Returns the elapsed time in seconds after theSpeechSynthesisUtterance.text started being spoken that the event was triggered at.
SpeechSynthesisEvent.nameRead only: Returns the name associated with certain types of events occurring as theSpeechSynthesisUtterance.text is being spoken: the name of theSSML marker reached in the case of amark event, or the type of boundary reached in the case of aboundary event.
SpeechSynthesisEvent.utteranceRead only: Returns theSpeechSynthesisUtterance instance that the event was triggered on.

Instance methods

TheSpeechSynthesisEvent interface also inherits methods from its parent interface,Event.

Examples

utterThis.onpause = (event) => {  const char = event.utterance.text.charAt(event.charIndex);  console.log(    `Speech paused at character ${event.charIndex} of "${event.utterance.text}", which is "${char}".`,  );};utterThis.onboundary = (event) => {  console.log(    `${event.name} boundary reached after ${event.elapsedTime} seconds.`,  );};