Declare keypress event should be fired when pressing Enter, Shift + Enter and Ctrl + Enter

[masayuki-nakano]

Currently, keypress event is declared as:

If supported by a user agent, this event MUST be dispatched when a key is pressed down, if and only if that key normally produces a character value.

However, in any browsers, Enter, Shift + Enter, Ctrl + Enter causes keypress event in any desktop OSes.

Unfortunately, whether keypress event is fired for Alt + Enter and Meta + Enter, and also 2 or modifiers + Enter depends on browser and platform...

[masayuki-nakano]

• Firefox (65~): Enter, Shift+Enter, Ctrl+Enter
• Edge: Enter, Shift+Enter, Ctrl+Enter
• Chrome on Windows: Enter, Shift+Enter, Ctrl+Enter
• Chromium on Linux: Enter, Shift+Enter, Ctrl+Enter, Shift+Ctrl+Enter, Super+Enter, Super+Shift+Enter, Super+Ctrl+Enter, Super+Shift+Ctrl+Enter
• Chrome on macOS: Enter, Shift+Enter, Ctrl+Enter, Shift+Ctrl+Enter, Alt+Enter, Shift+Alt+Enter, Alt+Ctrl+Enter, Shift+Alt+Ctrl+Enter
• Safari: Enter, Shift+Enter, Ctrl+Enter, Shift+Ctrl+Enter, Alt+Enter, Shift+Alt+Enter, Alt+Ctrl+Enter, Command+Enter, Shift+Command+Enter, Ctrl+Command+Enter, Alt+Command+Enter, Shift+Ctrl+Command+Enter, Shift+Alt+Command+Enter, Shift+Alt+Ctrl+Command+Enter

[masayuki-nakano]

@garykac Could you take a look this issue? This inconsistency could cause making incompatible web apps.