:default CSS pseudo-class
- WDThe :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
- 4 - 14: Support unknown
- 15 - 50: Partial support
- 51 - 112: Supported
- 113: Supported
- 114 - 116: Supported
Edge
- 12 - 18: Not supported
- 79 - 112: Supported
- 113: Supported
Safari
- 3.1 - 5: Support unknown
- 5.1 - 10: Partial support
- 10.1 - 16.4: Supported
- 16.5: Supported
- 16.6 - TP: Supported
Firefox
- 2 - 3.6: Support unknown
- 4 - 112: Supported
- 113: Supported
- 114 - 115: Supported
Opera
- 9 - 11.5: Support unknown
- 11.6 - 12.1: Partial support
- 15 - 37: Partial support
- 38 - 98: Supported
- 99: Supported
IE
- 5.5 - 10: Not supported
- 11: Not supported
Chrome for Android
- 113: Supported
Safari on iOS
- 3.2 - 6.1: Support unknown
- 7 - 10.2: Partial support
- 10.3 - 16.4: Supported
- 16.5: Supported
Samsung Internet
- 4: Partial support
- 5 - 20: Supported
- 21: Supported
Opera Mini
- all: Partial support
Opera Mobile
- 10 - 12: Support unknown
- 12.1: Partial support
- 73: Supported
UC Browser for Android
- 13.4: Supported
Android Browser
- 2.1 - 3: Support unknown
- 4 - 4.4.4: Partial support
- 113: Supported
Firefox for Android
- 113: Supported
QQ Browser
- 13.1: Supported
Baidu Browser
- 13.18: Supported
KaiOS Browser
- 2.5: Supported
- 3: 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.