Pass in a jQuery representation of an element ($container) you get markdown out.

HTMLToMarkdown.js

function htmlToMarkdown($container) {
	var $clone = $container.clone();
	$("*",$clone).removeAttr("name").removeAttr("title").removeAttr("id")		
	var html = $clone.html();
	html = standardiseHTML(html);
   	html = html.replace(/<a [^h]*href=["']([^"']*)["'][^>]*>([^<]*)<\/a>/gi, " [$2]($1)");
	html = html.replace(/<em[^>]*>([^<]*)<\/em>/gi,"*$1*");
	html = html.replace(/<strong[^>]*>([^<]*)<\/strong>/gi,"**$1**");
   	html = html.replace(/<i[^>]*>([^<]*)<\/i>/gi,"*$1*");
   	html = html.replace(/<b[^>]*>([^<]*)<\/b>/gi,"**$1**");
   	html = html.replace(/<p[^>]*>([^<]*)<\/p>/gi,"$1\n\n");
   	html = html.replace(/<li[^>]*>([^<]*)<\/li>/gi," - $1\n");
   	html = html.replace(/<ol[^>]*>([^<]*)<\/ol>/gi,"\n\n$1\n");		
   	html = html.replace(/<ul[^>]*>([^<]*)<\/ul>/gi,"\n\n$1\n");	
   	html = html.replace(/<blockquote[^>]*>/gi,"<blockquote>\n");	
   	html = html.replace(/<\/blockquote[^>]*>/gi,"<\/blockquote>\n");	
	$clone = $("<div />");
	if($.browser.msie) {
		html = html.replace(/\n(.*)\n/gi,"<p>$1</p>")
	}
	$clone.html(html);
	blockquoteToQuote($clone);
	html = $clone.html();
	html = html.replace(/&gt;/g,">").replace(/&lt;/g, "<");	
   	html = html.replace(/<\/?[^>]*>/g,"");
	html = html.replace(/\n /gi,"\n");
   	html = html.replace(/>[ ]{2,}\[C/g,"> [C");
   	return "\n" + html;
}


function standardiseHTML(html) {
	html = html.replace(/\b/g,"**REPLACE**").replace(/\*\*REPLACE\*\*/g,"");
	html = html.replace(/<(\/?)(\w+)>/gi, "<$1$2>");
	if($.browser.msie) {
		html = html.replace(/<LI>/g,"</LI><LI>").replace(/<([O|U])L><\/LI>/g,"<$1L>")
	} else {
		html = html.replace(/\n\s+/gi," ");
	}
	return html;
}

function blockquoteToQuote($container) {
	$("blockquote", $container).each(function(){
		if($(this).children("blockquote").size()>0) {
			blockquoteToQuote($(this));
		}				
		if($.browser.msie){
			$(this).html($(this).html().replace("<P></P>",">"));
			$("p", $(this)).prepend("> ");
			$(this).html($(this).html().replace("</P>","\r\n<P>> </P>"));
		} else {
			$(this).html($(this).html().replace(/\n/g,"\n > "));
		}
	});			
}