How does Etherpad listen to user input?

[marialovesbeans]

Specifically, on international keyboard (for example writing Chinese), user types some PinYin and select the Chinese character with mouse. That ONLY triggers compositionend event. And I dont see compositionend is telling Etherpad a new character is been inputted? This doesn't cause a keypress event. So how Etherpad know compositionend has made a change to DOM?

Lastly, why are we not using MutationObserver to observe changed to contenteditable? Is this a reason for this design?

Thanks a lot!