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

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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.


:optional {
  /* ... */


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.


HTML Standard
# selector-optional
Selectors Level 4
# opt-pseudos

Browser compatibility

BCD tables only load in the browser

See also