PHP Markdown is a port to PHP of the Markdown syntax by John Gruber. Markdown syntax allows users to write text naturally and format it without using HTML tags.

The PHP library converts that syntax from Markdown to HTML and back if needed. The library comes in an enhanced form, known as PHP Markdown Extra.
This special version of PHP Markdown implements some features currently not available with the plain Markdown syntax.

Features of PHP Markdown:
- Inline HTML
- Markdown Inside HTML Blocks
- Header Id Attribute
- Fenced Code Blocks
- Tables
- Definition Lists
- Footnotes
- Abbreviations
- Emphasis
- Backslash Escapes

Requirements:
- PHP 4.0.5 or Higher

What's New in this version:
- Enabled reference-style shortcut links.
- Now accepting many valid email addresses in autolinks that were previously rejected.
- Now accepting spaces in URLs for inline and reference-style links.
- Fix for adjacent list of different kind where the second list could end as a sublist of the first when not separated by an empty line.
- Fixed a bug where inline-style links wouldn’t be recognized when the link definition contains a line break between the url and the title.
- Fixed a bug where tags where the name contains an underscore aren’t parsed correctly.
- Fixed some corner-cases mixing underscore-ephasis and asterisk-emphasis.