@IBAction func loginBtn(_ sender: Any) {

        let username = userEmailTextField.text;
        let password = userPasswordTextField.text;


        if (username!.isEmpty || password!.isEmpty)
        {
            displayMyAlertMessage(userMessage: "All fields are equired.");
            return;
        }

        let urlString = "https://lenchan139.org/myWorks/fyp/android/attendDetails.php?username=" + username! + "&password=" + password!;

        let url = URL(string: urlString)
        URLSession.shared.dataTask(with:url!) { (data, response, error) in
            if error != nil {
                print(error!)
            } else {
                do {

                    let parsedData = try JSONSerialization.jsonObject(with: data!, options: []) as! [String:Any]
                    //print(parsedData);
                    let isVaild = parsedData["isVaild"] as! Bool;
                    let loggedUser = parsedData["username"] as? String;
                    //let dictStudAttend = parsedData["studArray"] as? NSArray;

                    //print(loggedUser!)
                    print(isVaild)
                    //print(dictStudAttend ?? NSArray())


                    var output : String;
                    if(isVaild == true){
                        output = loggedUser! + " is vaild";
                        /*for i in 0...dictStudAttend?.count-1{
                            let row = dictStudAttend[i] as! NSDictionary;
                            let name = row["student_name"] as? String;
                            print("student " + String(i) + "'s name is " + name!);

                        }*/

                        UserDefaults.standard.set(true, forKey: "isLoggedIn");
                        UserDefaults.standard.synchronize();

                        UserDefaults.standard.set(username, forKey: "username");
                        UserDefaults.standard.set(password, forKey: "password");
                        UserDefaults.standard.synchronize()
                        //let username = UserDefaults.standard.string(forKey: "username");
                        //print(username!);

                    }else if(loggedUser != nil){
                        output = loggedUser! + " is not vaild";


                    }else{
                        output = "InVaild!";

                        UserDefaults.standard.set(false, forKey: "isLoggedIn");
                        UserDefaults.standard.synchronize();
                        let isLoggedIn = UserDefaults.standard.bool(forKey: "isLoggedIn");
                        print(isLoggedIn)

                    }

                    print(output);
                } catch let error as NSError {
                    print(error)
                }
            }

            }.resume()
        let isLoggedIn = UserDefaults.standard.bool(forKey: "isLoggedIn");
        if (isLoggedIn == true) {
            performSegue(withIdentifier: "homePage", sender: self)
        }


}