ajax调用：响应<->数据类型

I simply want to submit form data (JS) to php script. I am using following code:

    form.children("div").steps({
        headerTag: "h3",
        bodyTag: "section",
        transitionEffect: "slideLeft",
        onStepChanging: function (event, currentIndex, newIndex){


            form.validate().settings.ignore = ":enabled,:hidden";
            return form.valid();
        },
        onFinishing: function (event, currentIndex){
            form.validate().settings.ignore = ":enabled";;
            return form.valid();
            },
        onFinished: function (event, currentIndex, name){
            var name = JSON.stringify($("#userName").val());
            var password =JSON.stringify( $("#password").val());

            $.ajax({
                url: "getInfo.php",
                type: "POST",
                dataType: "json",
                data: {username: name, password: password},
                success: function(response) {
                    $('#response').append(response);                        
                }

            });

        }
    });

The script "getInfo" receives the sent data "username" and password" and can perform further actions like db calls etc. Now I want to echo a table like:

echo "table..[some data]..";

But the correspondig div "response" remains empty.. If I change the dataType to "text", the .append actually appends something (although not correctly..) but now the webserver throws an error concerning a constant which is used somewhere else in the php script..

I think I am missing a basic thing here, but I really did not find a solution...

echo in json_encode(array()) in your "getInfo.php" because your datatype is json