Convert a limited set of Markdown to HTML - specifically bold, italics, and links. This is useful in basic chat environments where you do not want block content (images, paragraphs, etc).

gistfile1.js

String.prototype.markdown2html = function () {
    var text = this;
    // Bold
    text = text.replace(/(\*\*|__)(?=\S)([^\r]*?\S[*_]*)\1/g, "<strong>$2</strong>");
    // Italics
    text = text.replace(/(\*|_)(?=\S)([^\r]*?\S)\1/g, "<em>$2</em>");
    // Auto-detect links and convert them to markdown
    text = text.replace(/(\]\()?((https?|ftp|dict):[^'">\s]+)/gi, function($0, $1, $2) { return $1?$0:"[" + $2 + "](" + $2 + ")"});
    // Inline Links
    text = text.replace(/(\[((?:\[[^\]]*\]|[^\[\]])*)\]\([ \t]*()<?(.*?(?:\(.*?\).*?)?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\))/g, '<a href="$4">$2</a>');
    
    return text;
};