:default CSS pseudo-class

- WD

The :default pseudo-class matches checkboxes and radio buttons which are checked by default, <option>s with the selected attribute, and the default submit button (if any) of a form.

Chrome

  1. 4 - 14: Support unknown
  2. 15 - 50: Partial support
  3. 51 - 105: Supported
  4. 106: Supported
  5. 107 - 109: Supported

Edge

  1. 12 - 18: Not supported
  2. 79 - 104: Supported
  3. 105: Supported

Safari

  1. 3.1 - 5: Support unknown
  2. 5.1 - 10: Partial support
  3. 10.1 - 15.6: Supported
  4. 16.0: Supported
  5. 16.1 - TP: Supported

Firefox

  1. 2 - 3.6: Support unknown
  2. 4 - 104: Supported
  3. 105: Supported
  4. 106 - 107: Supported

Opera

  1. 9 - 11.5: Support unknown
  2. 11.6 - 12.1: Partial support
  3. 15 - 37: Partial support
  4. 38 - 90: Supported
  5. 91: Supported

IE

  1. 5.5 - 10: Not supported
  2. 11: Not supported

Chrome for Android

  1. 105: Supported

Safari on iOS

  1. 3.2 - 6.1: Support unknown
  2. 7 - 10.2: Partial support
  3. 10.3 - 15.6: Supported
  4. 16.0: Supported
  5. 16.1: Supported

Samsung Internet

  1. 4: Partial support
  2. 5 - 17.0: Supported
  3. 18.0: Supported

Opera Mini

  1. all: Partial support

Opera Mobile

  1. 10 - 12: Support unknown
  2. 12.1: Partial support
  3. 64: Supported

UC Browser for Android

  1. 13.4: Supported

Android Browser

  1. 2.1 - 3: Support unknown
  2. 4 - 4.4.4: Partial support
  3. 105: Supported

Firefox for Android

  1. 104: Supported

QQ Browser

  1. 13.1: Supported

Baidu Browser

  1. 13.18: Supported

KaiOS Browser

  1. 2.5: Supported

Whether <option selected> matches :default (per the spec) was not tested since <select>s and <option>s are generally not styleable, which makes it hard to formulate a test for this.

Resources:
WebKit bug 156230 - `:default` CSS pseudo-class should match checkboxes+radios with a `checked` attribute
MDN Web Docs - CSS :default
HTML specification for `:default`
JS Bin testcase