Access duration of a video

[szanuje]

Hey, is it possible to access the duration of a video?
Inside the Iframe, I can see a <video> element, which, according to the docs contains duration property.
https://www.w3schools.com/tags/ref_av_dom.asp
I was thinking, if I could access the video element and read that prop, in my React app?
For example, use query selector:
const v = document.querySelector("body > stream > div > video");
However, it doesn't seem to work for me.
Is it possible to access the duration?