Something

 drupal_add_js("$(document).ready(function(){
    var add_choice = document.createElement('input');
    add_choice.id = 'addChoice';
    add_choice.type = 'button';
    add_choice.value = '" . t('Add choice') . "';
    $('#edit-morechoices').append(add_choice);
    $('#addChoice').show('fast');
    $('#edit-morechoices').bind('click', function () {
      alert('clicked');
    });

  });", 'inline');