Why do we need disabled=“disabled”?

Question

It seems to be common consensus that for XHTML attributes which do not require any value, we should repeat the attribute name. E.g. in co

Answer 1

There is documentation for this, the official term for these kind of attributes is "Boolean Attributes"

The official standard is on the W3C website http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.4.2

It says that:

Their appearance in the start tag of an element implies that the value of the attribute is "true". Their absence implies a value of "false".

For your XHTML mark-up to be valid, you must use the long-hand

For HTML, you can use the minimised form