HTML Imports

- WD

Deprecated method of including and reusing HTML documents in other HTML documents. Superseded by ES modules.

IE

  1. 5.5 - 9: Not supported
  2. 10: Not supported (but has polyfill available)
  3. 11: Not supported (but has polyfill available)

Edge

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

Firefox

  1. 2 - 29: Not supported
  2. 30 - 31: Not supported (but has polyfill available)
  3. 32 - 55: Disabled by default
  4. 56 - 73: Not supported (but has polyfill available)
  5. 74: Not supported (but has polyfill available)
  6. 75 - 76: Not supported (but has polyfill available)

Chrome

  1. 4 - 29: Not supported
  2. 30 - 34: Disabled by default
  3. 35: Disabled by default
  4. 36 - 79: Supported
  5. 80: Not supported
  6. 81 - 83: Not supported

Safari

  1. 3.1 - 5.1: Not supported
  2. 6 - 12.1: Not supported (but has polyfill available)
  3. 13: Not supported (but has polyfill available)
  4. 13.1 - TP: Not supported (but has polyfill available)

Opera

  1. 9 - 16: Not supported
  2. 17 - 21: Disabled by default
  3. 22: Disabled by default
  4. 23 - 65: Supported
  5. 66: Supported

iOS Safari

  1. 3.2 - 6.1: Not supported
  2. 7 - 13.2: Not supported (but has polyfill available)
  3. 13.3: Not supported (but has polyfill available)
  4. 13.4: Not supported (but has polyfill available)

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 80: Not supported

Blackberry Browser

  1. 7: Not supported
  2. 10: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 46: Supported

Chrome for Android

  1. 80: Not supported

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: Supported

Samsung Internet

  1. 4 - 10.1: Supported
  2. 11.1: Supported

QQ Browser

  1. 1.2: Supported

Baidu Browser

  1. 7.12: Supported

KaiOS Browser

  1. 2.5: Supported
Resources:
IE Web Platform Status and Roadmap: HTML Imports
Firefox tracking bug: Implement HTML Imports
Chromium tracking bug: Implement HTML Imports
HTML5Rocks - HTML Imports: #include for the web
Polymer project (polyfill & web components framework)