This is a simple proyect to test the Web API of
MediaRecorder.
This is not a replacement for a professional recording software, nor it tries
to be, it is made to record simple things in your monitor. If you do need a
more robust recording application, I recommend you to use OBS Studio. It's a open source recording and streaming application, and it's
completely free to use.
This application uses the getDisplayMedia API to get the stream of your screen, and then uses the MediaRecorder API to record the stream. The recording is done in your browser, so no information is sent to any server. If you're wondering, yes, this uses your pc resources to do the recording.