An attribute extends an element, changing its behavior or providing metadata.
An attribute always has the form name="value" (the attribute's identifier followed by its associated value).
You may see attributes without the equals sign or a value. That is a shorthand for providing the empty string in HTML, or the attribute’s name in XML.
<input required>
<!-- is the same as… -->
<input required="">
<!-- or -->
<input required="required">
Learn more
Technical reference
- HTML attribute reference
- Information about HTML's global attributes