Ajax function some browsers do not support!

Ajax function some browsers do not support!

Hi!

I have this ajax function that executes till some output is done, but it doesn't work in some browsers like ie 6 or 7, please let me know if it is bad constructed:

  1.    <script type="text/javascript">
                var opt = {
                    type: "POST",
                    url: "ajaxfunct.php",
                    data: "param=343",
                    success: function(data) {
                        $("#p309_mailsender").html(data);
                        if (data != 'FINISHED') {
                            $.doTimeout( 3000, $.ajax(opt));
                        }
                    }
                };
     
                $.ajax(opt);
     
       </script>