<script>
    if ($(window).width() > 959) {
        $(document).ready(function () {
            var mreccalled = false;
            var scroll_height = $(window).scrollTop() + $(window).height(),
                MREC = 'div-gpt-ad-MREC';
            function offset(id) {
                var offset_top = $('#' + id).offset().top;
                return offset_top;
            }
            function loaded(id, bolean) {
                var loaded = (bolean) ? $('#' + id).attr('loaded', bolean) : $('#' + id).attr('loaded');
                return loaded;
            }
            function loadMREC(div_id) {
                mreccalled = true;
                if (!loaded(div_id)) {

                    loaded(div_id, true);
                    if (div_id == MREC) {
                        var link = '/2744311/ChoosePH_MREC';
                        var size = [[336, 280], [300, 250]];
                        var Mmapping = googletag.sizeMapping()
                            .addSize([568, 0], [[336, 280], [300, 250]])
                            .addSize([0, 0], [[336, 280], [300, 250]])
                            .build();
                    }
                    var gad = googletag.defineSlot(link, size, div_id).defineSizeMapping(Mmapping).addService(googletag.pubads());
                    googletag.enableServices();
                    googletag.display(div_id);
                    googletag.pubads().refresh([gad]);
                }
            };
            $(window).scroll(function () {
                if ($(window).scrollTop() + $(window).height() >= offset(MREC)) {
                    if (mreccalled == false) {
                        loadMREC(MREC);
                    }
                }
            });
        })
    }
</script>