Autofocus attribute

- LS

Allows a form field to be immediately focused on page load.

IE

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

Edge

  1. 12 - 86: Supported
  2. 87: Supported

Firefox

  1. 2 - 3.6: Not supported
  2. 4 - 82: Supported
  3. 83: Supported
  4. 84 - 85: Supported

Chrome

  1. 4: Not supported
  2. 5 - 86: Supported
  3. 87: Supported
  4. 88 - 90: Supported

Safari

  1. 3.1 - 4: Not supported
  2. 5 - 13.1: Supported
  3. 14: Supported
  4. TP: Supported

Opera

  1. 9: Not supported
  2. 9.5 - 71: Supported
  3. 72: Supported

iOS Safari

  1. 3.2 - 13.7: Not supported
  2. 14: Not supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 2.3: Not supported
  2. 3 - 4.4.4: Supported
  3. 81: Supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 59: Supported

Chrome for Android

  1. 87: Supported

Firefox for Android

  1. 83: Supported

UC Browser for Android

  1. 12.12: Not supported

Samsung Internet

  1. 4 - 12.0: Supported
  2. 13.0: Supported

QQ Browser

  1. 10.4: Supported

Baidu Browser

  1. 7.12: Supported

KaiOS Browser

  1. 2.5: Not supported

While not supported in iOS Safari, it does work in iOS WebViews.

Resources:
Article on autofocus
MDN Web Docs - autofocus attribute