Try this one http://jsfiddle.net/jaredwilli/tZPg4/4/
and use array so input should be something like this
<input type="text" name="data[1][time][start]">
<input type="text" name="data[1][time][end]">
<input type="text" name="data[2][time][start]">
<input type="text" name="data[2][time][end]">
….
then save data as array
update_post_meta($post_id, 'field_name', $_POST['data']);