Empty newlines not show up on preview using parsedown and codeigniter

Question

I am using parsedown and codeigniter. On my textarea if I have added a few empty lines they do not show up in preview. It only adds one \n in preview box

As shown in this image Note: preview is the bottom box in image

As you can see in the top box which is a textarea. There is a large gap just before the last line. It does not show that in preview? If I try and replace the newlines with br or nlbr it effects the indented code on parsedown

Question using codeigniter and parsedown how can I make sure when I echo it from controller that the will show same ammount of lines.

Script

<script type="text/javascript">
$( document ).ready(function() {
    $('#editor').on('paste cut mouseup mousedown mouseout keydown keyup', function(){
        var postData = {
            'html' : $('#editor').val(),
        };
        $.ajax({
            type: "POST",
            url: "<?php echo base_url('example/preview');?>",
            data: postData,
            dataType: 'json',
            success: function(json){
                $('#output').html(json['output']);
            }
        });
    });
});
</script>

Controller

<?php

class Example extends CI_Controller {

public function __construct() {
    parent::__construct();
    $this->load->library('parsedown');
}

public function index()
{
    $this->load->view('example_view');
}

public function preview() {
    $data['success'] = false;
    $data['output'] = '';

    if ($this->input->post('html')) {
        $data['success'] = true;
        // Using br or nlbr effect the code indents so can not use it.
        $data['output'] = str_replace('\n', '<br/>', $this->parsedown->text($this->input->post('html')));
    }

    echo json_encode($data);
}

Answer 1

You need to use double break tags to create a blank line.

ie

Something on this line
<br><br>
This line has a blank line above it.

You can work out what is needed for more than one blank line.

Have a play in http://parsedown.org/demo to test it.