.load与.get在Rails中

I am reading about AJAX in jQuery in the book jQuery in Action. There is some code which loads html into a div with an onchange event in a select dropdown. Using $.get looks like this:

$(function() {

  $('#bootChooserControl').change(function(event){
    $.get(
      '/fetch_product_details',
      $(this).serialize()
    );
  });
});

I have my controller respond to JavaScript:

fetch_product_details.js.erb

$('#productDetailPane').html('<%= j render "product_details" %>');

Now the next example switches to $.load and looks like this:

$('#bootChooserControl').change(function(event){
  $('#productDetailPane').load(
    '/fetch_product_details',
    $(this).serialize()
});

But for some reason the #productDetailPane is now filled with the following text:

$('#productDetailPane').html('

 Item name:<\/label> Chippewa 17-inch Engineer Boot
<\/div>


 SKU:<\/label> 7141832
<\/div>


 Height:<\/label> 17 inches
<\/div>


 Colors:<\/label> Black Oi
...

Just curious why the $.load function does not interpret the JavaScript?