`:required` CSS pseudo-class

The :required CSS pseudo-class represents any <input>, <select>, or <textarea> element that has the required attribute set on it.

label {
  display: block;
  margin-top: 1em;
}

.req {
  color: red;
}

*:required {
  background-color: gold;
}

<form>
  <label for="name">Name: <span class="req">*</span></label>
  <input id="name" name="name" type="text" required />

  <label for="birth">Date of Birth:</label>
  <input id="birth" name="birth" type="date" />

  <label for="origin"
    >How did you find out about us? <span class="req">*</span></label
  >
  <select id="origin" name="origin" required>
    <option>Google</option>
    <option>Facebook</option>
    <option>Advertisement</option>
  </select>
  <p><span class="req">*</span> - Required field</p>
</form>

This pseudo-class is useful for highlighting fields that must have valid data before a form can be submitted.

[!NOTE] The :optional pseudo-class selects optional form fields.

Syntax

:required {
  /* ... */
}

Accessibility

Mandatory <input>s should have the required attribute applied to them. 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 submission.

If the form also contains optional inputs, required inputs should 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.

• MDN Understanding WCAG, Guideline 3.3 explanations
• Understanding Success Criterion 3.3.2 | W3C Understanding WCAG 2.0

Examples

The required field has a red border

HTML

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

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

CSS

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

.field {
  margin: 1px;
  padding: 1px;
}

input:required {
  border-color: maroon;
  border-width: 3px;
}

input:required:invalid {
  border-color: #c00000;
}

Result

Specifications

Browser compatibility

See also

• Other validation-related pseudo-classes: :optional, :invalid, :valid
• Form data validation