SpeechSynthesisUtterance: boundary event

{{APIRef("Web Speech API")}}

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

Syntax

Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}} , or set an event handler property.

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

onboundary = (event) => { }

A {{domxref("SpeechSynthesisEvent")}} . Inherits from {{domxref("Event")}} .

{{InheritanceDiagram("SpeechSynthesisEvent")}}

In addition to the properties listed below, properties from the parent interface, {{domxref("Event")}} , are available.

{{domxref("SpeechSynthesisEvent.charIndex", "charIndex")}} {{ReadOnlyInline}}
- : Returns the index position of the character in the {{domxref("SpeechSynthesisUtterance.text")}} that was being spoken when the event was triggered.
{{domxref("SpeechSynthesisEvent.elapsedTime", "elapsedTime")}} {{ReadOnlyInline}}
- : Returns the elapsed time in seconds after the {{domxref("SpeechSynthesisUtterance.text")}} started being spoken that the event was triggered at.
{{domxref("SpeechSynthesisEvent.name", "name")}} {{ReadOnlyInline}}
- : Returns the name associated with certain types of events occurring as the {{domxref("SpeechSynthesisUtterance.text")}} is being spoken: the name of the SSML marker reached in the case of a {{domxref("SpeechSynthesisUtterance.mark_event", "mark")}} event, or the type of boundary reached in the case of a boundary event.
{{domxref("SpeechSynthesisEvent.utterance", "utterance")}} {{ReadOnlyInline}}
- : Returns the {{domxref("SpeechSynthesisUtterance")}} instance that the event was triggered on.

You can use the boundary event in an addEventListener method:

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

Or use the onboundary event handler property:

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

{{Specifications}}

{{Compat}}