In a Web form, the HTML <optgroup> element  creates a grouping of options within a <select> element.

Content categories:
None.

Permitted content:
Zero or more <option> elements.

Tag omission:
The start tag is mandatory. The end tag is optional if this element is immediately followed by another <optgroup> element, or if the parent element has no more content.

Permitted parent elements:
A <select> element.

DOM interface:
HTMLOptGroupElement
