If I open youtube, navigate to a video and run the following in the browser console, it works flawlessly.
const video = document.getElementById("movie_player")
video.getDuration()
If I'm making a chrome extension where the content script injects a button on the page at the document's end, and pressing the button executes the above code; it will give me undefined.
I'm not making my own iframe, I'm working with what's already on youtube. And it doesn't seem to matter how long I wait for before I press the button, it will always give me undefined.
Are we supposed to use the youtube API v3 to deal with this? because I was under the impression that it was designed to be used for when you want to tinker with your own iframes.