XHTML+SMIL animation

- UNOFF

Method of using SMIL animation in web pages

IE

  1. 5.5: Not supported
  2. 6 - 8: Partial support
  3. 9 - 10: Not supported
  4. 11: Not supported

Edge

  1. 12 - 18: Not supported
  2. 79: Not supported (but has polyfill available)
  3. 80: Not supported (but has polyfill available)

Firefox

  1. 2 - 72: Not supported (but has polyfill available)
  2. 73: Not supported (but has polyfill available)
  3. 74 - 75: Not supported (but has polyfill available)

Chrome

  1. 4 - 79: Not supported (but has polyfill available)
  2. 80: Not supported (but has polyfill available)
  3. 81 - 83: Not supported (but has polyfill available)

Safari

  1. 3.1 - 12.1: Not supported (but has polyfill available)
  2. 13: Not supported (but has polyfill available)
  3. TP: Not supported (but has polyfill available)

Opera

  1. 9 - 65: Not supported (but has polyfill available)
  2. 66: Not supported (but has polyfill available)

iOS Safari

  1. 3.2 - 13.1: Not supported (but has polyfill available)
  2. 13.2: Not supported (but has polyfill available)
  3. 13.3: Not supported (but has polyfill available)

Opera Mini

  1. all: Not supported (but has polyfill available)

Android Browser

  1. 2.1 - 4.4.4: Not supported (but has polyfill available)
  2. 80: Not supported (but has polyfill available)

Blackberry Browser

  1. 7: Not supported (but has polyfill available)
  2. 10: Not supported (but has polyfill available)

Opera Mobile

  1. 10 - 12.1: Not supported (but has polyfill available)
  2. 46: Not supported (but has polyfill available)

Chrome for Android

  1. 80: Not supported (but has polyfill available)

Firefox for Android

  1. 68: Not supported (but has polyfill available)

IE Mobile

  1. 10: Not supported
  2. 11: Not supported

UC Browser for Android

  1. 12.12: Not supported (but has polyfill available)

Samsung Internet

  1. 4 - 9.2: Not supported (but has polyfill available)
  2. 10.1: Not supported (but has polyfill available)

QQ Browser

  1. 1.2: Not supported (but has polyfill available)

Baidu Browser

  1. 7.12: Not supported (but has polyfill available)

KaiOS Browser

  1. 2.5: Not supported (but has polyfill available)

Internet Explorer supports the W3C proposal HTML+TIME, which is largely the same as XHTML+SMIL

Resources:
JS library to support XHTML+SMIL
Wikipedia