SpeechSynthesisUtterance: mark event

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.

Themark event of theWeb Speech API SpeechSynthesisUtterance object is fired when the spoken utterance reaches a named SSML "mark" tag.

Syntax

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

addEventListener("mark", (event) => { })onmark = (event) => { }

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.

You can use themark event in anaddEventListener method:

utterThis.addEventListener("mark", (event) => {  console.log(`A mark was reached: ${event.name}`);});

Or use theonmark event handler property:

utterThis.onmark = (event) => {  console.log(`A mark was reached: ${event.name}`);};

Specification
Web Speech API # eventdef-speechsynthesisutterance-mark
Web Speech API # dom-speechsynthesisutterance-onmark

This page was last modified on⁨May 2, 2025⁩ byMDN contributors.