url – ajax loaded but no JS

Try this code in your complete callback of the load function:

$(".postbox_wrapper").load(
    jQuery(this).attr("href") + " .postbox_wrapper",
    function(response, status, xhr) { // complete callback

        // create a empty div
        var div = document.createElement('div');
        // fill div with response
        div.innerHTML = response;
        // take correct part of the response
        var ref = $($(div).find('.postbox_wrapper').html());
        // filter response for script tags
        ref.filter('script').each(function () {
            // execute the scripts
            $.globalEval(this.text || this.textContent || this.innerHTML || '');
        });
    }
});

I would also also recommend that you add a error message if the call fails.
See example 2 on http://api.jquery.com/load/

I had a hard time to figure that out, I tried all the answers found on stackoverflow.
Finally I found this german site. There you can see the full code: http://labor.99grad.de/flash/agentur/wiesbaden/jquery/script-tag-bei-ajax-response-ausfuhren/