(Note: EditContext can be enabled through #enable-experimental-web-platform-features in about://flags)

Click somewhere in the Canvas below, start typing Chinese/Japanese/Korean,
(and change candidate characters) to see how EditContext works with Canvas to handle IME input:

To try the "phrase" mode in Japanese IME (on Windows),
1) type "konosushihaoishiidesu" and press "space".
2) use left/right key to move between phrases and press "space" to open the candidate window
3) use up/down key to choose candidate, press "Esc" to close the candidate window or press "Enter" to commit