How can I count the table rows that is added dynamically with jQuery?

I have tried with `$('#mytbody').children().length;` but it doesn't work with rows that are added dynamically.

Here is my code, also [runnable in JsFiddle](http://jsfiddle.net/H8sBr/)

```
<!DOCTYPE html>
<html>
<head>
<script src="jquery-1.6.2.min.js">
<script>
$(function() {
    $('#add').bind('click', function() {
        $('#mytbody').after('<tr><td>'+ new Date() +'</td></tr>');
        var count = $('#mytbody').children().length;
        $('#counter').html(count);
    });
});
</script>
</head>
<body>
<button id="add">Add row</button>
<table>
    <tbody id="mytbody">
    </tbody>
</table>
Number of rows: <span id="counter"></span>
</body>
</html>

```