CSS position:fixed

- REC

Method of keeping an element in a fixed location regardless of scroll position

IE

  1. 5.5: Not supported
  2. 6: Not supported (but has polyfill available)
  3. 7 - 10: Supported
  4. 11: Supported

Edge

  1. 12 - 79: Supported
  2. 80: Supported

Firefox

  1. 2 - 71: Supported
  2. 72: Supported
  3. 73 - 74: Supported

Chrome

  1. 4 - 79: Supported
  2. 80: Supported
  3. 81 - 83: Supported

Safari

  1. 3.1 - 9: Supported
  2. 9.1: Supported
  3. 10 - 12.1: Supported
  4. 13: Supported
  5. TP: Supported

Opera

  1. 9 - 65: Supported
  2. 66: Supported

iOS Safari

  1. 3.2 - 4.3: Not supported
  2. 5 - 7.1: Partial support
  3. 8 - 13.1: Supported
  4. 13.2: Supported
  5. 13.3: Supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 2.3: Partial support
  2. 3: Supported
  3. 4 - 4.3: Supported
  4. 4.4 - 4.4.4: Supported
  5. 76: Supported

Blackberry Browser

  1. 7: Supported
  2. 10: Supported

Opera Mobile

  1. 10 - 12.1: Supported
  2. 46: Supported

Chrome for Android

  1. 79: Supported

Firefox for Android

  1. 68: Supported

IE Mobile

  1. 10: Supported
  2. 11: Supported

UC Browser for Android

  1. 12.12: Supported

Samsung Internet

  1. 4 - 9.2: Supported
  2. 10.1: Supported

QQ Browser

  1. 1.2: Supported

Baidu Browser

  1. 7.12: Supported

KaiOS Browser

  1. 2.5: Supported
Resources:
Article on mobile support
Workaround for IE6
WebPlatform Docs