CustomEvent

- LS

A DOM event interface that can carry custom application-defined data.

Chrome

  1. 4: Not supported
  2. 5 - 8: Support unknown
  3. 9 - 12: Partial support
  4. 13 - 14: Support unknown
  5. 15 - 107: Supported
  6. 108: Supported
  7. 109 - 111: Supported

Edge

  1. 12 - 106: Supported
  2. 107: Supported

Safari

  1. 3.1 - 4: Not supported
  2. 5: Support unknown
  3. 5.1: Partial support
  4. 6: Support unknown
  5. 6.1 - 16.0: Supported
  6. 16.1: Supported
  7. 16.2 - TP: Supported

Firefox

  1. 2 - 5: Not supported
  2. 6 - 10: Partial support
  3. 11 - 106: Supported
  4. 107: Supported
  5. 108 - 109: Supported

Opera

  1. 9 - 10.6: Not supported
  2. 11 - 11.5: Partial support
  3. 11.6 - 91: Supported
  4. 92: Supported

IE

  1. 5.5 - 8: Not supported
  2. 9 - 10: Partial support
  3. 11: Partial support

Chrome for Android

  1. 107: Supported

Safari on iOS

  1. 3.2: Support unknown
  2. 4: Not supported
  3. 4.2: Support unknown
  4. 5: Partial support
  5. 6 - 16.0: Supported
  6. 16.1: Supported

Samsung Internet

  1. 4 - 18.0: Supported
  2. 19.0: Supported

Opera Mini

  1. all: Supported

Opera Mobile

  1. 10: Not supported
  2. 11 - 11.5: Partial support
  3. 12 - 12.1: Supported
  4. 72: Supported

UC Browser for Android

  1. 13.4: Supported

Android Browser

  1. 2.1 - 2.3: Not supported
  2. 3 - 4.3: Partial support
  3. 4.4 - 4.4.4: Supported
  4. 107: Supported

Firefox for Android

  1. 106: Supported

QQ Browser

  1. 13.1: Supported

Baidu Browser

  1. 13.18: Supported

KaiOS Browser

  1. 2.5: Supported

Not supported in some versions of Android's old WebKit-based WebView.

Resources:
MDN Web Docs - CustomEvent
EventListener polyfill which includes a CustomEvent polyfill
Polyfill based on the MDN snippet