Can I use
?

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 - 130: Supported
  6. ✅ 131: Supported
  7. ✅ 132 - 134: Supported

Edge

  1. ✅ 12 - 130: Supported
  2. ✅ 131: Supported

Safari

  1. ❌ 3.1 - 4: Not supported
  2. ﹖ 5: Support unknown
  3. ◐ 5.1: Partial support
  4. ﹖ 6: Support unknown
  5. ✅ 6.1 - 18.0: Supported
  6. ✅ 18.1: Supported
  7. ✅ 18.2 - TP: Supported

Firefox

  1. ❌ 2 - 5: Not supported
  2. ◐ 6 - 10: Partial support
  3. ✅ 11 - 131: Supported
  4. ✅ 132: Supported
  5. ✅ 133 - 135: Supported

Opera

  1. ❌ 9 - 10.6: Not supported
  2. ◐ 11 - 11.5: Partial support
  3. ✅ 11.6 - 113: Supported
  4. ✅ 114: Supported

IE

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

Chrome for Android

  1. ✅ 131: Supported

Safari on iOS

  1. ﹖ 3.2: Support unknown
  2. ❌ 4: Not supported
  3. ﹖ 4.2: Support unknown
  4. ◐ 5: Partial support
  5. ✅ 6 - 18.0: Supported
  6. ✅ 18.1: Supported
  7. ✅ 18.2: Supported

Samsung Internet

  1. ✅ 4 - 25: Supported
  2. ✅ 26: Supported

Opera Mini

  1. ✅ all: Supported

Opera Mobile

  1. ❌ 10: Not supported
  2. ◐ 11 - 11.5: Partial support
  3. ✅ 12 - 12.1: Supported
  4. ✅ 80: Supported

UC Browser for Android

  1. ✅ 15.5: Supported

Android Browser

  1. ❌ 2.1 - 2.3: Not supported
  2. ◐ 3 - 4.3: Partial support
  3. ✅ 4.4 - 4.4.4: Supported
  4. ✅ 131: Supported

Firefox for Android

  1. ✅ 132: Supported

QQ Browser

  1. ✅ 14.9: Supported

Baidu Browser

  1. ✅ 13.52: Supported

KaiOS Browser

  1. ✅ 2.5: Supported
  2. ✅ 3: 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