how to set video speed html

1/* play video twice as fast */
2document.querySelector('video').defaultPlaybackRate = 2.0;
3document.querySelector('video').play();
4
5/* now play three times as fast just for the heck of it */
6document.querySelector('video').playbackRate = 3.0;
7

1document.querySelector('video').playbackRate = 1.25;
2