if (typeof markdown === 'undefined') var markdown = {
parse: function (s) {
    var r = s, ii, pre1 = [], pre2 = [];

    // detect newline format
    var newline = r.indexOf('\r\n') != -1 ? '\r\n' : r.indexOf('\n') != -1 ? '\n' : ''
    
    // store CONSTANT "{ unformatted blocks": not defined !} and 
 pre-formatted blocks 
    r = r.replace(/CONSTANT "{": not defined !}/g, function (x) { pre1.push(x.substring(3, x.length - 3)); return 'CONSTANT "{": not defined !}'; });
    r = r.replace(new RegExp('
([\\s\\S]*?)
', 'gi'), function (x) { pre2.push(x.substring(5, x.length - 6)); return '
'; });
    
    // h1 - h4 and hr
    r = r.replace(/^==== (.*)=*/gm, '
$1
');
    r = r.replace(/^=== (.*)=*/gm, '
$1
');
    r = r.replace(/^== (.*)=*/gm, '
$1
');
    r = r.replace(/^= (.*)=*/gm, '
$1
');
    r = r.replace(/^[-*][-*][-*]+/gm, '
');
    
    // bold, italics, and code formatting
    r = r.replace(/\*\*(.*?)\*\*/g, '$1');
    r = r.replace(new RegExp('//(((?!https?://).)*?)//', 'g'), '$1');
    r = r.replace(/``(.*?)``/g, '$1');
    
    // unordered lists
    r = r.replace(/^\*\*\*\* (.*)/gm, '
$1
');
    r = r.replace(/^\*\*\* (.*)/gm, '
$1
');
    r = r.replace(/^\*\* (.*)/gm, '
$1
');
    r = r.replace(/^\* (.*)/gm, '
$1
');
    for (ii = 0; ii < 3; ii++) r = r.replace(new RegExp('' + newline + '
', 'g'), newline);
    
    // ordered lists
    r = r.replace(/^#### (.*)/gm, '
$1
');
    r = r.replace(/^### (.*)/gm, '
$1
');
    r = r.replace(/^## (.*)/gm, '
$1
');
    r = r.replace(/^# (.*)/gm, '
$1
');
    for (ii = 0; ii < 3; ii++) r = r.replace(new RegExp('' + newline + '
', 'g'), newline);
    
    // links
    r = r.replace(/\[\[(http:[^\]|]*?)\]\]/g, '$1');
    r = r.replace(/\[\[(http:[^|]*?)\|(.*?)\]\]/g, '$2');
    r = r.replace(/\[\[([^\]|]*?)\]\]/g, '$1');
    r = r.replace(/\[\[([^|]*?)\|(.*?)\]\]/g, '$2');
    
    // images
    r = r.replace(/{{([^\]|]*?)}}/g, '');
    r = r.replace(/{{([^|]*?)\|(.*?)}}/g, '');
    
    // video
    r = r.replace(/<<(.*?)>>/g, '');
    
    // hard linebreak if there are 2 or more spaces at the end of a line
    r = r.replace(new RegExp(' + ' + newline, 'g'), '
' + newline);
    
    // 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++) {
        var blockLevel = false;
        if (p[i].length >= 1 && p[i].charAt(0) == '<') {
            // check if the first tag is a block-level element
            var firstSpace = p[i].indexOf(' '), firstCloseTag = p[i].indexOf('>');
            var endIndex = firstSpace > -1 && firstCloseTag > -1 ? Math.min(firstSpace, firstCloseTag) : firstSpace > -1 ? firstSpace : firstCloseTag;
            var tag = p[i].substring(1, endIndex).toLowerCase();
            for (var j = 0; j < blockLevelElements.length; j++) if (blockLevelElements[j] == tag) blockLevel = true;
        } else if (p[i].length >= 1 && p[i].charAt(0) == '|') {
            // format the paragraph as a table
            blockLevel = true;
            p[i] = p[i].replace(/ \|= /g, '').replace(/\|= /g, '').replace(/ \|=/g, '');
            p[i] = p[i].replace(/ \| /g, '').replace(/\| /g, '').replace(/ \|/g, '');
            p[i] = '' + p[i] + '';
        } else if (p[i].length >= 2 && p[i].charAt(0) == '>' && p[i].charAt(1) == ' ') {
            // format the paragraph as a blockquote
            blockLevel = true;
            p[i] = '
' + p[i].replace(/^> /gm, '') + '
';
        }
        if (!blockLevel) p[i] = '
' + p[i] + '
';
    }
    
    // reassemble the paragraphs
    if (newline != '') r = p.join(newline + newline);
    
    // restore the preformatted and unformatted blocks
    r = r.replace(new RegExp('
', 'g'), function (match) { return '
' + pre2.shift() + '
'; });
    r = r.replace(/CONSTANT "{": not defined !}/g, function (match) { return pre1.shift(); });
    return r;
}
};

// markdown.parse(myText)

/*
= Heading 1
== Heading 2
=== Heading 3
==== Heading 4

**bold**
//italic//

* Bullet list
* Second item
** Sub item

# Numbered list
# Second item
## Sub item

[[link]]
CONSTANT "image": not defined !
<