Is it possible to make a screen recording of an entire page in a browser window?
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.