Theboundary event of theWeb Speech API is fired when the spoken utterance reaches a word or sentence boundary.

Syntax

Use the event name in methods likeaddEventListener(), or set an event handler property.

addEventListener("boundary", (event) => { })onboundary = (event) => { }

Event type

ASpeechSynthesisEvent. Inherits fromEvent.

Event properties

In addition to the properties listed below, properties from the parent interface,Event, are available.

charIndexRead only

Returns the index position of the character in theSpeechSynthesisUtterance.text that was being spoken when the event was triggered.

elapsedTimeRead only

Returns the elapsed time in seconds after theSpeechSynthesisUtterance.text started being spoken that the event was triggered at.

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.

utteranceRead only

Returns theSpeechSynthesisUtterance instance that the event was triggered on.

Examples

You can use theboundary event in anaddEventListener method:

utterThis.addEventListener("boundary", (event) => {  console.log(    `${event.name} boundary reached after ${event.elapsedTime} seconds.`,  );});

Or use theonboundary event handler property:

utterThis.onboundary = (event) => {  console.log(    `${event.name} boundary reached after ${event.elapsedTime} seconds.`,  );};

Specifications

Browser compatibility

See also

• Web Speech API