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...