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SpeechSynthesisEvent

The SpeechSynthesisEvent interface of the Web Speech API contains information about the current state of SpeechSynthesisUtterance objects that have been processed in the speech service.

Constructor

SpeechSynthesisEvent(): Creates a new SpeechSynthesisEvent.

Instance properties

The SpeechSynthesisEvent interface also inherits properties from its parent interface, Event.

SpeechSynthesisEvent.charIndex Read only: Returns the index position of the character in the SpeechSynthesisUtterance.text that was being spoken when the event was triggered.
SpeechSynthesisEvent.charLength Read only: Returns the number of characters left to be spoken after the charIndex position, if the speaking engine supports it. Returns 0 if the speaking engine can't provide the information.
SpeechSynthesisEvent.elapsedTime Read only: Returns the elapsed time in seconds after the SpeechSynthesisUtterance.text started being spoken that the event was triggered at.
SpeechSynthesisEvent.name Read only: Returns the name associated with certain types of events occurring as the SpeechSynthesisUtterance.text is being spoken: the name of the SSML marker reached in the case of a mark event, or the type of boundary reached in the case of a boundary event.
SpeechSynthesisEvent.utterance Read only: Returns the SpeechSynthesisUtterance instance that the event was triggered on.

Instance methods

The SpeechSynthesisEvent 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.`,
  );
};

Specifications

Specification
Web Speech API # speechsynthesisevent

Browser compatibility