WordPress + JavaScipt + AJAX + MySQL: insert query for form

I’ve cleaned everything a little bit. Now it looks like that:

ajax.js

function ajaxSubmit(e){
var nazwa_szkolenia = document.getElementById("nazwa_szkolenia").value;
var Data_szkolenia = document.getElementById("Data_szkolenia").value;
var Godzina = document.getElementById("Godzina").value;
var Max_pacjent = document.getElementById("Max_pacjent").value;

var dataString = [];
dataString['nazwa_szkolenia1'] = nazwa_szkolenia;
dataString['Data_szkolenia1'] = Data_szkolenia;
dataString['Godzina1'] = Godzina;
dataString['Max_pacjent1'] = Max_pacjent;

if (nazwa_szkolenia == '' || Data_szkolenia == '' || Godzina == '' || Max_pacjent == '') {
alert("Wypełnij wszystkie pola");
} else {
    // prevent the default action.
    e.preventDefault();

    //var myform= jQuery(this).serialize();

    jQuery.ajax({
        type:"GET",
        // Get the admin ajax url which we have passed through wp_localize_script().
        url: ajax_object.ajax_url,
        action: "submitAjaxForm",
        data: dataString,
        error: function(jqXHR, textStatus, errorThrown){                                        
        console.error("The following error occured: " + textStatus, errorThrown);                                                       
    },
        success:function(data){
console.log(dataString);
        }
    });
}
return false;
}

arcode-functions.php:

<?php

function registerFormAction(){
    add_action('wp_ajax_nopriv_submitAjaxForm','submitAjaxForm_callback');
    add_action('wp_ajax_submitAjaxForm','submitAjaxForm_callback');
}
    
function submitAjaxForm_callback(){
   global $wpdb;
    
    $nazwa_szkolenia2 = $_GET['nazwa_szkolenia1'];
    $Data_szkolenia2 = $_GET['Data_szkolenia1'];
    $Godzina_szkolenia2 = $_GET['Godzina1'];
    $Max_pacjent2 = $_GET['Max_pacjent1'];

        $result = $wpdb->insert( $wpdb->modul_terminarz, array( 
                                  'Nazwa_szkolenia' => $nazwa_szkolenia2, 
                                  'Data_szkolenia' => $Data_szkolenia2, 
                                  'Godzina_szkolenia' => $Godzina_szkolenia2,
                                  'Typ_szkolenia' => '1',
                                  'Ile_miejsc_max' => $Max_pacjent2,
                                  'Pelna_obsada' => '0',
                                  ) );

    wp_die();   
}


add_action('init', 'registerFormAction');

?>
        

that code stays in my menu.php:

// Hook for adding admin menus

 add_action('admin_menu', 'create_Terminarz_menu');
 
 // action function for above hook
 
/**
 * Adds a new top-level page to the administration menu.
 */
function create_Terminarz_menu() {

     add_menu_page(
        'ARCode Terminarz',
        'Terminarz',
        'manage_options',
        'zarzadzanie-terminami',
        'tm_zarzadzanie_terminami_odp',
        plugins_url('images/terminarz.png', __FILE__),'2.2.10'
    );
    
     add_submenu_page( 'zarzadzanie-terminami', 'ARCode Terminarz' . 'Terminy szkoleń', '<b style="color:#E46500;">Terminy szkoleń</b>', 'manage_options', 'zarzadzanie-terminami', 'tm_zarzadzanie_terminami_odp');
     add_submenu_page( 'zarzadzanie-terminami', 'ARCode Terminarz' . 'Pacjenci', 'Pacjenci', 'manage_options', 'pacjenci', 'tm_zarzadzanie_pacjentami_odp');
      add_action('admin_enqueue_scripts','load_custom_wp_admin_js');
}

/**
 * Display callback for the Unsub page.
 */
 function tm_zarzadzanie_pacjentami_odp() {
     
 }
 
 
 
 function load_custom_wp_admin_js($hook){
    wp_register_script( 'jquery.min.js', plugin_dir_url( __FILE__ ) . 'js/jquery.min.js', array('jquery'));
    wp_enqueue_script( 'jquery.min.js' );
    wp_enqueue_style( 'kalendarz',plugin_dir_url( __FILE__ ) . 'kalendarz.css',false,'1.1','all' );
    wp_register_script( 'ajax-script', plugin_dir_url( __FILE__ ) . 'ajax_js.js');
    wp_localize_script('ajax-script', 'ajax_object', array('ajax_url' => admin_url('admin-ajax.php')));
    wp_enqueue_script( 'ajax-script', plugin_dir_url( __FILE__ ) . 'ajax_js.js');
}

 
 /**
 * Display callback for the Unsub page.
 */
 function tm_zarzadzanie_terminami_odp() {
     include_once( 'arcode-functions.php');
     include_once( 'kalendarz.php');
     
     ?>
     <div class="wrap" style="position: fixed;
          width: 85%;
          top: 40px;
          bottom: 80px;">
     </div>
     <?php

 }
    

In kalendarz.php I have all functions for booking calendar and forms, this is the form which I need to send:

this.createFormular = function () {
             var ob = this.o;
             
             var Admin_Form = document.createElement('form')
             Admin_Form.name="Formularz_Admin";
             Admin_Form.method='GET';
             Admin_Form.action='';

             var tabela = document.createElement('table');
             tabela.className="formular-table";
            
             var tr = document.createElement('tr');
             tabela.appendChild(tr);
             var td = document.createElement('td');
             td.appendChild(document.createTextNode('Nazwa szkolenia:   '));
             tr.appendChild(td);
             tr.appendChild(td);
             
             td.appendChild(Input_Name_Training);
             
             var tr = document.createElement('tr');
             tabela.appendChild(tr);
             var td = document.createElement('td');
             td.appendChild(document.createTextNode('Data szkolenia:   '));
             tr.appendChild(td);
             tr.appendChild(td);
             
             td.appendChild(Input_Date_Training);
             
             var tr = document.createElement('tr');
             tabela.appendChild(tr);
             var td = document.createElement('td');
             td.appendChild(document.createTextNode('Godzina szkolenia:   '));
             tr.appendChild(td);
             tr.appendChild(td);
             
             td.appendChild(Input_Hour_Training);
             
             var tr = document.createElement('tr');
             tabela.appendChild(tr);
             var td = document.createElement('td');
             td.appendChild(document.createTextNode('Max ilość osób:   '));
             tr.appendChild(td);
             tr.appendChild(td);
             
             td.appendChild(Input_How_Many_People);          
             
             
             var tr = document.createElement('tr');
             tabela.appendChild(tr);
             var td = document.createElement('td');
             td.appendChild(document.createTextNode('   '));
             tr.appendChild(td);
             tr.appendChild(td);
             
             td.appendChild(Input_Form_Send);       
              
             Admin_Form.appendChild(tabela);
             
             this.divForm.appendChild(Admin_Form);
             

         };

I’ve tried to check if submitAjaxFormis working, I’ve checked it with echo as scott said, but it gives nothing. DataString gives right Array, but data gives 0…
I don’t know what I make wrong ;/ I don’t see if hook to register for submitAjaxForm is bad, in my opinion all hooks are ok…?