How to get only the content ($body_code) of the page without headers and sideboxes?

I am trying to implement ajax on my shop. I have all the working files but when I try to implement ajax on zencart, it shows the entire page with headers, footers and sideboxes. All I want for that particular page is the content of the $body_code variable. Does anyone know how to achieve this?

I found a solution for this. Not sure if this is the best way to do this. If you have a better way, share your views.

In includes/templates/YOURTEMPLATE/common/tpl_main_page.php, I modified the code like this:

if ($_REQUEST['main_page'] == "PAGENAME") { // added

$flag_disable_left = true;
$flag_disable_right = true;
$flag_disable_header = true;
$flag_disable_footer = true;
require($body_code);

} else {

    // your existing code

}