Web/CSS/ default

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 §4.16.3 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>’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.

Syntax

:default

Examples

HTML

<fieldset>
  <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>
</fieldset>

CSS

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

input:default + label {
  color: coral;
}

Result

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of ':default' in that specification.	Living Standard	No change.
HTML5The definition of ':default' in that specification.	Recommendation	Defines associated HTML semantics and constraint validation.
Selectors Level 4The definition of ':default' in that specification.	Working Draft	No change.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`:default`	Chrome Full support 10	Edge Full support 79	Firefox Full support 4	IE No support No	Opera Full support 10	Safari Full support 5	WebView Android Full support 37	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 5	Samsung Internet Android Full support 1.0

Legend

Full support: Full support
No support: No support