Web Sockets

- LS

Bidirectional communication technology for web apps

Chrome

  1. 4 - 14: Partial support
  2. 15: Partial support
  3. 16 - 116: Supported
  4. 117: Supported
  5. 118 - 120: Supported

Edge

  1. 12 - 116: Supported
  2. 117: Supported

Safari

  1. 3.1 - 4: Not supported
  2. 5 - 5.1: Partial support
  3. 6 - 6.1: Partial support
  4. 7 - 16.5: Supported
  5. 16.6: Supported
  6. 17.0 - TP: Supported

Firefox

  1. 2 - 3.6: Not supported
  2. 4 - 5: Partial support
  3. 6 - 10: Partial support
  4. 11 - 116: Supported
  5. 117: Supported
  6. 118 - 120: Supported

Opera

  1. 9 - 10.6: Not supported
  2. 11 - 12: Partial support
  3. 12.1 - 101: Supported
  4. 102: Supported

IE

  1. 5.5 - 9: Not supported
  2. 10: Supported
  3. 11: Supported

Chrome for Android

  1. 117: Supported

Safari on iOS

  1. 3.2 - 4.1: Not supported
  2. 4.2 - 5.1: Partial support
  3. 6 - 16.6: Supported
  4. 17.0: Supported
  5. 17.1: Supported

Samsung Internet

  1. 4 - 21: Supported
  2. 22: Supported

Opera Mini

  1. all: Not supported

Opera Mobile

  1. 10: Not supported
  2. 11 - 12: Partial support
  3. 12.1: Supported
  4. 73: Supported

UC Browser for Android

  1. 15.5: Supported

Android Browser

  1. 2.1 - 4.3: Not supported
  2. 4.4 - 4.4.4: Supported
  3. 117: Supported

Firefox for Android

  1. 117: Supported

QQ Browser

  1. 13.1: Supported

Baidu Browser

  1. 13.18: Supported

KaiOS Browser

  1. 2.5: Supported
  2. 3: Supported

Reported to be supported in some Android 4.x browsers, including Sony Xperia S, Sony TX and HTC.

Resources:
Details on newer protocol
MDN Web Docs - WebSockets API
Wikipedia
has.js test
WebPlatform Docs