Markdown
http://daringfireball.net/projects/markdown/
2016-08-03
Markdown is a markup language that uses simple marker symbols for Web page formatting for plain text, and then uses the compiler to convert it into rich, structured HTML documents.
Markdown is stored in plain text format, the default suffix is MD, its format is easy to read and easy to edit. Using Markdown to write Help or description documents that you need to format, and even to write documents, publications, and so on, is easier.
The GitHub website uses the Markdown editor, which has some features added, and most famous websites use it as an online editor, so it's necessary to learn the markdown.
Dingus is an online application that provides test markdown to directly convert the input markdown code into HTML and preview it.
The official Website Syntax page provides a complete markdown syntax, and GitHub specializes in a tutorial site and mastering Markdwon tutorials.
Markdown: Simple Markup Language for Web page layout with plain text