HyperText Markup Language (HTML) vs AsciiDoc

Styling through CSS is declarative and powerful, but somewhat inadequate for print without expensive tools like Prince.

Natively understood by browsers, you can author and view HTML on virtually every computer without any additional software.

HTML is fairly simple for both humans and machines. It can be repetitive and burdensome to type, but less so than most other XML or SGML-derived formats.

JavaScript code can be embedded directly into a HTML document.

The formatting of Asciidoc is standardized so there is only one 'flavor' unlike in Markdown. The definitive user guide is here.

Simple, easy-to-read style similar to Markdown. Designed to be easy for a human to enter with a simple text editor, and easy to read in its raw form.

The DocBook format which Asciidoctor can convert to was originally developed with the creation of computer books in mind and thus has a rich array of formatting options which are powerful enough to manage the formatting of lengthy technical books.

Both GitHub and GitLab support AsciiDoc syntax in repositories, wikis and Gists/Snippets (powered by the Asciidoctor Ruby gem).

Cleanly transforms to DocBook and HTML5.

AsciiDoc has offered the ability to define both the color of any text output as well as its background, almost since its inception. It accepts several standard chromatic notations for them, too, including hexadecimal and decimal RGB values, decimal HSL and named CSS.

The AsciiDoc standard defines a number of metadata values which can be defined inside a document primarily for contextual purposes that aren't rendered in its standard output such as author, date, license, document title and version, etc. These can be especially useful when searching through a large number of files/documents or documenting the evolution of one as part of a larger codebase.

There are plugins to support editing AsciiDoc for many editors/IDEs.