What Are Radio Buttons?

Radio input elements are typically used in radio groups where only one button can be selected at a time. You can try out the radio button example to see how it works.

Using radio inputs

We already covered the fundamentals of radio buttons above. Let's now look at the other common radio-button-related features and techniques you may need to know about.

Selecting a radio button by default

To make a radio button selected by default, you include checked attribute, as shown in this revised version of the previous example:

<form>
  <fieldset>
    <legend>Please select your preferred contact method (email is the default):</legend>
    <div>
      <input
        type="radio"
        id="contactChoice1"
        name="contact"
        value="email"
        checked />
      <label for="contactChoice1">Email</label>

      <input type="radio" id="contactChoice2" name="contact" value="phone" />
      <label for="contactChoice2">Phone</label>

      <input type="radio" id="contactChoice3" name="contact" value="mail" />
      <label for="contactChoice3">Mail</label>
    </div>
    <div>
      <button type="submit">Submit</button>
    </div>
  </fieldset>
</form>

In this case, the first radio button is now selected by default.

Note: If you put the checked attribute on more than one radio button, later instances will override earlier ones; that is, the last checked radio button will be the one that is selected. This is because only one radio button in a group can ever be selected at once, and the user agent automatically deselects others each time a new one is marked as checked.

Providing a bigger hit area for your radio buttons

In the above examples, you may have noticed that you can select a radio button by clicking on its associated <label> element, as well as on the radio button itself. This is a really useful feature of HTML form labels that makes it easier for users to click the option they want, especially on small-screen devices like smartphones.

Beyond accessibility, this is another good reason to properly set up <label> elements on your forms.