aceholder div with id
     <code>
      <span>
       "myTarget{{prefix}}"
      </span>
     </code>
     and use it as a target in the input button.
    </p>
    <div>
     <p>
      Note
     </p>
     <p>
      <code>
       {{prefix}}
      </code>
      is a Jinja2 notation that means "use the value of the prefix variable, which PixieDust automatically creates to provide a unique id." We need this value to avoid a conflict in case a user calls the PixieApp multiple times within the same notebook.
    