<script>
    $(document).ready(function(){
        $(window).scroll(function(){
            var position = $(window).scrollTop();
            var bottom = $(document).height() - $(window).height();
            if( position == bottom ){
                var row = Number($('#row').val());
                var allcount = Number($('#all').val());
                var rowperpage = 3;
                row = row + rowperpage;
                if(row <= allcount){
                    $('#row').val(row);
                    $.ajax({
                        url: 'fetch_pages.php',
                        type: 'post',
                        data: {row:row},
                        success: function(response){
                            $(".col-md-3:last").after(response).show().fadeIn("slow");
                        }
                    });
                }
            }
        });
    });
</script>