var mdown = function (s) {
        var r = s;

        // detect newline format
        var newline = r.indexOf('\r\n') != -1 ? '\r\n' : r.indexOf('\n') != -1 ? '\n' : ''

        // h1 - h2 and hr
        r = r.replace(/^== (.*)=*/gm, '<h2>$1</h2>');
        r = r.replace(/^= (.*)=*/gm, '<h1>$1</h1>');
        r = r.replace(/^[-*][-*][-*]+/gm, '<hr>');

        // bold, italics
        r = r.replace(/\*\*(.*?)\*\*/g, '<strong>$1</strong>');
        r = r.replace(new RegExp('//(((?!https?://).)*?)//', 'g'), '<em>$1</em>');

        // unordered lists
        r = r.replace(/^\* (.*)/gm, '<ul><li>$1</li></ul>');
        r = r.replace(new RegExp('</ul>' + newline + '<ul>', 'g'), newline);

        // links & images
        r = r.replace(/\[\[([^|]*?)\|(.*?)\]\]/g, '<a href="$1">$2</a>');
        r = r.replace(/{{([^\]|]*?)}}/g, '<img src="$1">');

        // split on double-newlines, then add paragraph tags when the first tag isn't a block level element
        if(newline != '') {
            for(var p = r.split(newline + newline), i = 0; i < p.length; i++) {
                p[i] = '<p>' + p[i] + '</p>';
            }

            r = p.join(newline + newline); // reassemble the paragraphs
        }
        return r;
    }