<div id="loading" style="display: none;"></div>
<div id="modal" style="display: none;"></div>
$.ajax({
            url: $(this).attr('href'),
            beforeSend: function(){

                loading = $('#loading').dialog({
                    modal: true,
                    width: 100,
                    height: 100
                });
                $(".ui-dialog-titlebar").hide();

            },
            success: function(data){

                $('#modal').html(data);
                $('#modal').dialog({
                    modal: true,
                    width:'auto',
                });

                loading.dialog('close');
            }
        });