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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The elapsedTime read-only property of the SpeechSynthesisUtterance interface returns the elapsed time in seconds after the SpeechSynthesisUtterance.text started being spoken that the event was triggered at.




A float.


utterThis.onboundary = function(event) {
  console.log( + ' boundary reached after ' + event.elapsedTime + ' seconds.');


Specification Status Comment
Web Speech API
The definition of 'elapsedTime' in that specification.

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 33 (Yes) 49 (49) No support ? 7
Feature Android Chrome Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) No support 2.0 No support No support 7.1

See also

Document Tags and Contributors

 Contributors to this page: aarongustafson, abbycar, chrisdavidmills
 Last updated by: aarongustafson,