Remove eval()

In general, you should never use eval(). AJAX calls should return data, not logic. More specifically echo "$('#status').html('<b>The morse code is : ". $output ."</b>');"; should be more like drupal_json(array('morse' => $output)); And eval(msg); should be more like var response = $.parseJSON(msg); $('#status').html('<b>The morse code is : ' + response.morse + '</b>'); (This is untested code, but should give you the general idea.)