I thought the interesting thing was how it's a bitmask (a bit rare in IDL attributes / DOM properties). Also I was unaware there were 4th and (shock) 5th button

I thought the interesting thing was how it's a bitmask (a bit rare in IDL attributes / DOM properties). Also I was unaware there were 4th and (shock) 5th buttons for some mouses. So theoretically there's 32 possible states of pressing such a mouse. I wasn't aware JS surfaced this "multi touch" capability for buttons, as the bitmask indicates which buttons were pressed "at the same time" for whatever the event is (mouse/pointer down etc). Just thought it was cool and a little rare. Nice digging into the MDN docs and discover new parts of the DOM. Like a new room in a giant familiar house! :) For me at least haha :)