jQuery serialize error with textarea filed

I'm using this function, to submit form in the background, with custom messages. It works perfectly, except with textarea fields. I've read that the serialize function has problems with ex. linebreaks.

 $(function() {
      $("#comment_form").validate({    submitHandler: function(form) {
        $.post('/u/r/l/', $("#comment_form").serialize(),
 function(data) {
            $('#comment_container').html(data);
                });
            }
        });

The textarea is a markitup! editor area.

As stated here: http://api.jquery.com/serialize/#comment-67394779

function keepLB (str) { 
  var reg=new RegExp("(%0A)", "g");
  return str.replace(reg,"%0D$1");
}

$(function() {
  $("#comment_form").validate({ submitHandler: function(form) {
    $.post('/u/r/l/', keepLB($("#comment_form").formSerialize()), function(data) {
      $('#comment_container').html(data);
    });
  }
});

If it doesn't work, manually urlencode the textarea data:

$(function() {
  $("#comment_form").validate({ submitHandler: function(form) {
    $.post('/u/r/l/', "textareadata="+escape($("#mytextarea").value), function(data) {
      $('#comment_container').html(data);
    });
  }
});

And if you also want to send other form contents (note: don't give the textarea a "name" here, just an id!):

$(function() {
  $("#comment_form").validate({ submitHandler: function(form) {
    $.post('/u/r/l/',
    $("#comment_form").formSerialize()+"&textareadata="+escape($("#mytextarea").value),
    function(data) {
      $('#comment_container').html(data);
    });
  }
});