KeyboardEvent.which

- UNOFF

A legacy KeyboardEvent property that is equivalent to either KeyboardEvent.keyCode or KeyboardEvent.charCode depending on whether the key is alphanumeric.

IE

  1. 5.5 - 8
  2. 9 - 10
  3. 11

Edge

  1. 12 - 81
  2. 83

Firefox

  1. 2 - 75
  2. 76
  3. 77 - 78

Chrome

  1. 4 - 81
  2. 83
  3. 84 - 86

Safari

  1. 3.1 - 4
  2. 5
  3. 5.1 - 13
  4. 13.1
  5. TP

Opera

  1. 9 - 9.6
  2. 10 - 67
  3. 68

iOS Safari

  1. 3.2 - 4.3
  2. 5 - 13.3
  3. 13.4

Opera Mini

  1. all

Android Browser

  1. 2.1 - 2.2
  2. 2.3 - 4.3
  3. 4.4 - 4.4.4
  4. 81

Blackberry Browser

  1. 7
  2. 10

Opera Mobile

  1. 10 - 12.1
  2. 46

Chrome for Android

  1. 81

Firefox for Android

  1. 68

IE Mobile

  1. 10
  2. 11

UC Browser for Android

  1. 12.12

Samsung Internet

  1. 4
  2. 5 - 10.1
  3. 11.1

QQ Browser

  1. 10.4

Baidu Browser

  1. 7.12

KaiOS Browser

  1. 2.5

This property is legacy and deprecated. "Some key events, or their values, might be suppressed by the IME in use". On mobile (virtual keyboard), all keys are reported as 229.

Resources:
MDN Web Docs - which