Markdown is a lightweight markup language that allows people to write documents in a plain text format that is easy to read and write, and then convert them into valid XHTML (or HTML) documents. This language incorporates many of the features of plain text markup already found in email.
1. Markdown syntax;
2. The functions and uses of commonly used character tags in Markdown;
3. The relationship and conversion methods between Markdown and HTML;
4. Markdown commonly used writing tools
