Prototype AJAX responsetext missing the javascript

Question

I can find the JS and HTML code in response by alert(). But i cannot append JS from response to body tag however HTML is appending fine.

new Ajax.Request(product_url, {
    method: 'post',
    onSuccess: function(transport) {
         $$('body')[0].insert(transport.responseText);
    }
});

Answer 1

      new Ajax.Request(product_url, {
           method: 'post',
          onSuccess: function(transport) {

               $$('body')[0].insert(new Element("div",{id:"popup"}));
               $('popup').innerHTML = transport.responseText;
      }
    });

this gives the solution.