<script>

    function signUp()
    {
        $.post("accept.php", $("#newUserReg").serialize(),

  function(data){

alert(data);

  }, "json");

    }
</script>

İşte html formudur:

<form id = "newUserReg" name = "newUserReg" onsubmit() = "signUp(); return false;">
    <input id = "newField1" type = "text" />
    <input id = "newField2" type = "password" name = "newPwd" />
    <input type = "submit" />
</form>

Accept.php:

if(isset($_POST['newField1']))
    echo json_encode("adas");
else
    echo json_encode("adaasds");