title: Using Mage register when submitting values with ajax to controller
body: <p>I am trying to pass data from a controller to be used in the view.  What is happening is I am taking super attributes for the product that user selects (size and color) and all of that gets serialized and passed to the controller where I get a product object. From this object I am then able to get the configurable sku which I then need to echo out into the design view.phtml file.</p>
  
  <p>The function in the controller looks like :</p>
  
  <pre><code>if($product = $this-&gt;_initProduct())
          {
             $config = $product-&gt;getSku();
            // if I echo $config here using firephp I can see that this is correct value
             Mage::register('config_product', $config);
            // I am hoping to set it as a global variable here that 
            //  I can then retrieve on the success of the ajax function
          }
  </code></pre>
  
  <p>In the phtml I have something like this to send form values to that controller :</p>
  
  <pre><code> var data = $("#product_addtocart_form").serialize();
              $.ajax({
                  url: "/locator/item/index",
                  data: data
              }).done(function(){
                  &lt;?php $currentProduct = Mage::registry('config_product'); 
                   // Why does this return blank??
                   ?&gt;
                   &lt;?php Mage::helper('firephp')-&gt;send( $currentProduct ); ?&gt;                    
              });
  </code></pre>