Question

Why do we need a <fieldset> tag? Whatever purpose it serves is probably a subset of the form tag.

I looked up some info on W3Schools, which says:

• The <fieldset> tag is used to group related elements in a form.
• The <fieldset> tag draws a box around the related elements.

More explanation for those who are mistaking “why it exists in specification” for “what it does”.
I think the drawing part is irrelevant, and I don’t see why we need a special tag just to group some related elements in a form.

Answer 1

The most obvious, practical example is:

<fieldset>
  <legend>Colour</legend>

  <input type="radio" name="colour" value="red" id="colour_red">
  <label for="colour_red">Red</label>

  <input type="radio" name="colour" value="green" id="colour_green">
  <label for="colour_green">Green</label>

  <input type="radio" name="colour" value="blue" id="colour_blue">
  <label for="colour_blue">Blue</label>

</fieldset>

This allows each radio button to be labeled while also providing a label for the group as a whole. This is especially important where assistive technology (such as a screen reader) is being used where the association of the controls and their legend cannot be implied by visual presentation.