[jQuery] Some problems with ajax

Hello i'm trying to use jquery to do some ajax but having some
troubles... and i can't really figure why
javascript:
$("#recaptcha_response_field").keyup(function () {
                 var captcha = $("#recaptcha_response_field").val();
                    if(captcha.length >= 6){
                        $.ajax({
                            type: "POST",
                            url: "captcha_validate.php",
                            data: "dados=querty",
                            beforeSend: function(){ $("#loading").show("fast");},
                            sucess: function(msg){
                                alert(msg);
                            },
                            error: function(XMLHttpRequest, textStatus, errorThrown){
                                alert("error:" +errorThrown+ " text:" +textStatus);
                            },
                            complete: function(){ $("#loading").hide("fast");}
                        });
the php:
<?php
    sleep(1);
    header("Cache-Control: no-cache");
$captcha = $_POST['dados'];
    echo "bleh -> $captcha";
?>
Main problem here is i'm not getting either of the sucess or error
events, i get the beforesend and complete, so shouldn't i have a
sucess or error event?!?!
Thank you for any help!!! i really need it
Hugo Almeida.