How can I use "record" in javascript only?

[GabrielBarrachino]

I would like to know how to use "record" correctly in javascript. I have an animation made and I have a download button that would work as the "record". "Record" I'm referring to is the one on the scene.js demo site, the "record" button re-renders the animation into a video, in my case I want the download button to do the same function and if possible, do an automatic download