tot nu toe

form in profile.php

<form id="changepassword" action="/repos/database.php" method="GET" class="well">
      <div class="form-group">
        <label>Huidige wachtwoord</label>
        <input type="password" name="gebruikersnaam" class="form-control" placeholder="Voer wachtwoord in" >
      </div>
      <div class="form-group">
        <label>Nieuw wachtoord:</label>
        <input type="password" name="wachtwoord" class="form-control" placeholder="Nieuw wachtwoord" id="txtNewPassword" onchange="checkPasswordSafety();">
        <label id="errormeldingveld"> </label>
      </div>
      <div class="form-group">
        <label>Verifieer wachtoord:</label>
        <input type="password" name="confirmwachtwoord" class="form-control" placeholder="Verifieer nieuw wachtwoord" id="txtConfirmPassword" onchange="checkpasswordMatch();">
      </div>

        <div>
          <label id="divCheckPasswordMatch">
        </div>
      <button type="submit" class="btn btn-default btn-block"  >Verander wachtwoord</button>
  </form>

database.php
<?php
session_start();


$db = new database;




if($db->verifypassword()){
  header ("Location: /admin/index.php");
}else{
  header ("Location: /admin/login.php");
  #foutmelding geven op de pagina;
}


class database
{
  protected $mysqli ;


      function __construct(){

    $this->mysqli = new mysqli("localhost","root","","databasenaam");

    if ($this->mysqli->connect_errno) {
        echo "Failed to connect to MySQL: (" . $this->mysqli->connect_errno . ") " . $this->mysqli->connect_error."<br> Contact your database administrator when this error occurs";



    }else{

    }
    }

    function verifypassword(){

      $user = $_POST['gebruikersnaam'];
      $pwd = $_POST['wachtwoord'];



      $res = $this->mysqli->query("SELECT wachtwoord FROM inloggegevens WHERE gebruikersnaam = '$user'");

      $res->data_seek(0);//date seek 0 because there is only 1 result possible
      while ($row = $res->fetch_assoc()) {
          //echo " wachtwoord = " . $row['wachtwoord'] . "\n";

          if (password_verify($pwd, $row['wachtwoord']) ) {
            $_SESSION['ingelogd'] = $user;

            //echo "win";

            if (password_needs_rehash($row['wachtwoord'], PASSWORD_DEFAULT)) {
                    // Recalculate a new password_hash() and overwrite the one we stored previously

                      $this->updatepassword($pwd);
                }
                return true;

          }
          else
          {

           return false;

         }
      }

    }

    function updatepassword($nieuwwachtwoord){

      $hashedpwd = password_hash($nieuwwachtwoord,PASSWORD_BCRYPT);
       $this->mysqli->query("UPDATE inloggegevens SET wachtwoord = '$hashedpwd' WHERE gebruikersnaam = 'Admin'");
    }

    function createuser($createpassword, $username){
      $safepassword = password_hash($createpassword,PASSWORD_BCRYPT);
      $this->mysqli->query("INSERT INTO inloggegevens (gebruikersnaam, wachtwoord) VALUES ($username,$safepassword)");
    }


    function selectall(){
      $res = $this->mysqli->query("SELECT gebruikersnaam FROM inloggegevens ");
      return $res;
    }
}


?>