pass linebreaks through ajax to server from a content editable div

I've used editable for my div in order to make it easy to edit the contents of a web page but when the text is sent to the server using ajax the line breaks have been removed.   What's worse, I can't even detect them using a regular expression.   I've tried many combinations:

            alert($(this).siblings("#body_121").text().replace(/<br>/gm, 'xxx'));
            alert($(this).siblings("#body_121").text().replace(/\n/gm, 'xxx'));
            alert($(this).siblings("#body_121").text().replace(/the/g,"**the**"));
            alert($(this).siblings("#body_121").text().replace(/<br?\/>/g,"break"));
            alert($(this).siblings("#body_121").text().replace(/\r\n/g,"**rn***"));
            alert($(this).siblings("#body_121").text().replace(/\n\r/g,"**nr***"));
            alert($(this).siblings("#body_121").text().replace(/\n/g,"**nnn***"));
            alert($(this).siblings("#body_121").text().replace(/\r/g,"**rrr***"));
            alert($(this).siblings("#body_121").text().replace(/<br>/g,"**rrr***"));
            alert($(this).siblings("#body_121").text().replace(/\r\n|\r|\n/g,"\n"));
            alert($(this).siblings("#body_121").text().replace(/\n\r?/g, 'xxxxx%0D%0A'));
            alert($(this).siblings("#body_121").text().replace(/\x0A/g, '0a'));
            alert($(this).siblings("#body_121").text().replace(/\x0D/g, '0a'))

None of these works detects any line breaks.   Each alert just shows the string without line breaks.  
If i use firebug I can see the linebreaks being added
mmmmm
<br>
<br>
mmmmm
every time I hit enter a new linebreak is added.   I can detect any other character  but even this detects nothing:
alert($(this).siblings("#body_121").text().replace(/[^m]/g, 'xxx'))

If i add any other character it detects it. such as:

 mmmmmgmmm

the g will show up as:

mmmmmxxxmmm