Custom Elements (deprecated V0 spec)

- UNOFF

Original V0 version of the custom elements specification. See Custom Elements V1 for support for the latest version.

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 - 22: Not supported
  2. 23 - 29: Disabled by default
  3. 30 - 58: Disabled by default
  4. 59 - 72: Not supported
  5. 73: Not supported
  6. 74 - 75: Not supported

Chrome

  1. 4 - 26: Not supported
  2. 27 - 32: Disabled by default
  3. 33 - 79: Supported
  4. 80: Not supported
  5. 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. TP: Not supported (but has polyfill available)

Opera

  1. 9 - 12.1: Not supported
  2. 15 - 19: Disabled by default
  3. 20 - 65: Supported
  4. 66: Supported

iOS Safari

  1. 3.2 - 6.1: Not supported
  2. 7 - 13.1: Not supported (but has polyfill available)
  3. 13.2: Not supported (but has polyfill available)
  4. 13.3: Not supported (but has polyfill available)

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.4: Not supported
  2. 4.4.3: Supported
  3. 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

IE Mobile

  1. 10: Not supported
  2. 11: Not 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: Disabled by default
Resources:
Google Developers - Custom elements v1: reusable web components
document.registerElement polyfill in 3KB minified & gzipped
HTML5Rocks - Custom Elements: defining new elements in HTML
Polymer project (polyfill & web components framework)