The :default CSS pseudo-class selects form elements that are the default in a group of related elements.

What this selector matches is defined in HTML Standard ยง4.16.3 Pseudo-classes — it may match the <button>, <input type="checkbox">, <input type="radio">, and <option> elements:

  • A default option element is the first one with the selected attribute, or the first enabled option in DOM order. multiple <select>s can have more than one selected option, so all will match :default.
  • <input type="checkbox"> and <input type="radio"> match if they have the checked attribute.
  • <button> matches if it is a <form>โ€™s default submission button: the first <button> in DOM order that belongs to the form. This also applies to <input> types that submit forms, like image or submit.





  <legend>Favorite season</legend>

  <input type="radio" name="season" id="spring">
  <label for="spring">Spring</label>

  <input type="radio" name="season" id="summer" checked>
  <label for="summer">Summer</label>

  <input type="radio" name="season" id="fall">
  <label for="fall">Fall</label>

  <input type="radio" name="season" id="winter">
  <label for="winter">Winter</label>


input:default {
  box-shadow: 0 0 2px 1px coral;

input:default + label {
  color: coral;



Specification Status Comment
HTML Living Standard
The definition of ':default' in that specification.
Living Standard No change.
The definition of ':default' in that specification.
Recommendation Defines associated HTML semantics and constraint validation.
Selectors Level 4
The definition of ':default' in that specification.
Working Draft No change.

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
:defaultChrome Full support 10Edge Full support 79Firefox Full support 4IE No support NoOpera Full support 10Safari Full support 5WebView Android Full support 37Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 5Samsung Internet Android Full support 1.0


Full support
Full support
No support
No support

See also