FSBSchedule Login (JavaScript)

var xmlhttperror;
var RegisterXHR = XHRObject();
var LoginXHR = XHRObject();

function XHRObject() {
    var HttpRequestObject;

    if(window.XMLHttpRequest) {
        HttpRequestObject = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        try {
            HttpRequestObject = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                HttpRequestObject = new ActiveXObject("Microsoft.XMLHTTP");
            } catch(e) {
                HttpRequestObject = false;
            }
        }
    }

    return HttpRequestObject;
}

function SendRegistrationData(form) {
    var formData = new FormData(form);

    RegisterXHR.open('POST', 'http://taylorcopeland.com/fsbSchedule/register.php', true);
    RegisterXHR.onreadystatechange = RegisterSuccess;
    RegisterXHR.send(formData);

    return false; // Prevents page from submitting data (the old-fashioned way)
}

function SendLoginData(form) {
    var formData = new FormData(form);
    var LoginXHR = XHRObject();

    xhr.onreadystatechange = LoginSuccess;
    xhr.open('POST', 'http://taylorcopeland.com/fsbSchedule/doLogin.php', true);
    xhr.send(formData);

    return false;
}

function RegisterSuccess() {
    if(RegisterXHR.readyState === 4) {
        if(RegisterXHR.status === 200) {
            var error;
            switch(request.responseText) {
            case "Missing required form values.\n":
                // throw new Error("Missing required form values.");
                error = "Missing required form values.";
                return false;
                break;
            case "The email provided is already registered\n.":
                // throw new Error("That email is already registered.");
                error = "That email is already registered.";
                return false;
                break;
            case "The provided passwords did not match.\n":
                // throw new Error("Passwords do not match.");
                error = "Passwords do not match";
                return false;
                break;
            case "Successfully registered.\n":
                error = null;
                return true;
                break;
            default:
                // throw new Error("Something has gone horribly wrong.\n");
                error = "Something has gone horribly wrong.\n";
                return false;
                break;
            }
        }
    }
}

function LoginSuccess() {
    if(LoginXHR.readyState === 4) {
        if(LoginXHR.status === 200) {
            var error;
            switch(request.responseText) {
            case "Invalid email":
                error = "Invalid email address.";
                return false;
                break;
            case "Invalid password":
                error = "Invalid password";
                return false;
                break;
            default:
                error = null;
                return false;
                break;
            }
        }
    }
}