Target an options text area for a product in opencart for javascript code? -

im new opencart , javascript. trying target textarea option associated product in opencart can implement javascript code. @ moment have alert box appears when type in textarea, doesnt seem work. question, possible target these option textareas generated opencart end? below snippet of javascript code seems work on other textareas not on option textareas.

<script type="text/javascript"><!-- $(document).ready(function() {      $('.options').keyup(function() {         alert('test');     });  }); //--></script> 

append following snippet product.tpl, before last line <?php echo $footer; ?>

<script type="text/javascript"><!-- $(document).ready(function() {      $(".options textarea").keyup( function() {         alert('test');     }); }); //--></script>  

whenever input characters, there alert coming out.

notes: maybe hope 1 whenever mouse up, can bind mouseup event.