Load flexslider inside fancybox

load flexslider inside fancybox .js

$(".fancybox").fancybox({

            autoSize: false, // keep this and let the slider to resize itself
            afterLoad: function () {
                $('.overlay-slider').flexslider({
                    animation: "slide",
                    controlNav: false,
                    start: function () {
                        $("#overlay").show() // make parent container visible
                    }
                });
            }
        });