Is it possible to make a screen recording of an entire page in a browser window? I know how to take full-length screenshots of a given page, but what about video? Audio recording not necessary, but would be interested to know of any tactics or well-hidden browser extension recos for capturing a full page in all its animated glory.

Perhaps there's something about how the viewport handles graphics that makes recording off-screen animation unfeasible, so I encourage sharing efficient ways to stitch multiple videos or other reasonable (free? easy?) workarounds.
Apple buit this functionality into Quicktime player and many people don't know it's there. In fact you can even record the screen of a connected iPad or iPhone.

Open Quicktime player and select New Screen recording... You will be given some brief instructions and then a button to click to start recording. When you are done, right-click on the Quicktime dock icon and end the recording.