The :optional CSS pseudo-class represents any <input>, <select>, or <textarea> element that does not have the required attribute set on it.

/* Selects any optional <input> */
input:optional {
  border: 1px dashed black;

This pseudo-class is useful for styling fields that are not required to submit a form.

Note: The :required pseudo-class selects required form fields.




The optional field has a purple border


  <div class="field">
    <label for="url_input">Enter a URL:</label>
    <input type="url" id="url_input">

  <div class="field">
    <label for="email_input">Enter an email address:</label>
    <input type="email" id="email_input" required>


label {
  display: block;
  margin: 1px;  
  padding: 1px;

.field {
  margin: 1px;
  padding: 1px;
input:optional {
  border-color: rebeccapurple;
  border-width: 3px;


Accessibility concerns

If a form contains optional <input>s, required inputs should be indicated using the required attribute. This will ensure that people navigating with the aid of assistive technology such as a screen reader will be able to understand which inputs need valid content to ensure a successful form submission.

Required inputs should also be indicated visually, using a treatment that does not rely solely on color to convey meaning. Typically, descriptive text and/or an icon are used.


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

Browser compatibilityUpdate compatibility data on GitHub

Chrome Edge Firefox Internet Explorer Opera Safari
:optional 10 12 4 10 10 5
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
:optional 37 18 4 10.1 5 1.0

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.