Set Boolean Attributes

A boolean attribute is a built-in attribute that acts like a toggle. Its sole function is to turn on a feature or behavior.

Boolean attribute entry syntax

A boolean attribute is set with an attribute entry in the header or body of a document. Its value is always left blank because boolean attributes only accept an empty string value, which Asciidoctor automatically assigns at processing time.

:name-of-a-boolean-attribute: (1)

1	On a new line, type a colon (`:`), directly followed by the attribute’s name and then another colon (`:`). After the closing colon, press `Enter`. The attribute is now set and its behavior will be applied to the document.

Declare a boolean attribute

Let’s use an attribute entry to turn on the built-in boolean attribute named sectanchors. When sectanchors is set, it activates an anchor in front of a section title when a cursor hovers over it.

= Document Title
:sectanchors: (1)

1	The value of `sectanchors` is always left empty because it’s a boolean attribute.