<optgroup>
Groups related options under a label inside a select.
Baseline: Widely available · Forms
When to use it
When the option list has natural categories — the label renders as a non-selectable group heading.
When not to
Only valid inside select; don't nest optgroups.
Key attributes
label- the group heading (required)
disabled
Example
<select>
<optgroup label='Free'>
<option>Reader</option>
</optgroup>
<optgroup label='Paid'>
<option>Supporter</option>
</optgroup>
</select>