A PHP Markdown class which can parse markdown document and parse html as well.
#Usage:
require 'markdown.class.php';
$obj = new Markdown();
$mdFile = 'markdown_document.md'; //orig
$htmlFile = 'markdown_html.html';
$html2mdFile = 'html_2_md.md'; //parse
$md2htmlFile = 'md_2_html.html';
$mdBackFile = 'markdown_back.md'; //parse and parse back
$htmlBackFile = 'html_back.html';
$md = file_get_contents($mdFile);
$md2html = $obj->parseMarkdown($md);
file_put_contents($md2htmlFile, $md2html); //md => html
$html = file_get_contents($htmlFile);
$html2md = $obj->parseHtml($html);
file_put_contents($html2mdFile, $html2md); //html => md
$mdBack = $obj->parseHtml($md2html);
file_put_contents($mdBackFile, $mdBack); //md => html => md
$htmlBack = $obj->parseMarkdown($html2md);
file_put_contents($htmlBackFile, $htmlBack); //html => md => html