I have a form repeater (https://github.com/DubFriend/jquery.repeater) that adds multiple inputs if needed, but the only thing is.. i don't know how to make'it to insert in sql all the data from form at once. So here's what i have so far, sorry for my bad English, I am a learner and u guys are the best.
HTML:
<form action="" method="POST">
        <div class="modal-body">
          <div class="repeater-default">
            <div data-repeater-list="sectiuni" class="col-md-12">
              <div data-repeater-item="">
                <div class="row">
                  <div class="form-group mb-1 col-sm-12 col-md-4">
                    <label for="email-addr">Sectiunea</label>
                    <br>
                    <input type="text" class="form-control" id="sectiunea" name="sectiunea[]" placeholder="Introdu sectiunea">
                  </div>
                  <div class="form-group mb-1 col-sm-12 col-md-2">
                    <label for="pass">Nr.Dansatori</label>
                    <br>
                    <input type="number" class="form-control" name="nrdansatori[]" id="nrdansatori" placeholder="Numarul dansatorilor">
                  </div>
                  <div class="skin skin-flat form-group mb-1 col-sm-12 col-md-2">
                    <label for="tel-input">Timp piesa</label>
                    <br>
                    <input class="form-control" type="text" name="timpsectiune[]" id="timpsectiune" placeholder="2:34">
                  </div>
                  <div class="form-group mb-1 col-sm-12 col-md-2">
                    <label for="pret">Pret</label>
                    <br>
                    <input class="form-control" type="number" name="pretsectiune[]" id="pretsectiune" placeholder="250">
                  </div>
                  <div class="form-group col-sm-12 col-md-2 mt-1">
                    <button type="button" class="btn btn-danger" style="margin-top: 12px;" data-repeater-delete=""> <i
                        class="feather icon-trash"></i> Delete</button>
                  </div>
                  <hr>
                </div>
              </div>
            </div>
            <div class="form-group overflow-hidden">
              <div class="col-12">
                <button type="button" data-repeater-create="" class="btn btn-primary col-sm-12 btn-sm">
                  <i class="feather icon-plus"></i> ADD ONE MORE SECTION
                </button> 
              </div>
            </div>
          </div>
        </div>
        <div class="modal-footer">
          <input type="reset" class="btn btn-secondary" data-dismiss="modal" value="Close">
          <input type="submit" id="save" class="btn btn-success" value="Save">
        </div>
      </form>
Javascript:
$("#save").click(function(e) {
        e.preventDefault();
        var sectiunea    = $("#sectiunea").val();
        var nrdansatori  = $("#nrdansatori").val();
        var timpsectiune = $("#timpsectiune").val();
        var pretsectiune = $("#pretsectiune").val();
        var infos = {
            sectiunea   : sectiunea,
            nrdansatori : nrdansatori,
            timpsectiune: timpsectiune,
            pretsectiune: pretsectiune
        };
        $.ajax({
            type: 'POST',
            data: infos,
            url: 'sql-insert.php',
            success: function(data) {
                if (data === TRUE) {
                    alert('Success'); 
                } else {
                     alert("ERROR");
                }
            }
       });
PHP:
    if(isset($_POST['sectiunea'])) {
    $table = "`".RDCP_PREFIX."sectiuni`";
        $data = array(
            'sectiune' => trim($db->escape($_POST['sectiunea'])),
            'max_d'    => trim($db->escape($_POST['nrdansatori'])),
            'timp'     => trim($db->escape($_POST['timpsectiune'])),
            'pret'     => trim($db->escape($_POST['pretsectiune']))
          );
          foreach ($data as $name) {
         
         $db->insert($table, $data);
          
        }
    } 
public function insert($table,$fields) { 
$field = array_keys($fields); 
$single_field = implode(",", $field); 
$val = implode("','", $fields); 
$stmt = $this->conn->prepare("INSERT INTO ".$table."(".$single_field.") VALUES('".$val."')"); 
$stmt->execute(); 
if($stmt === true) { echo true; } 
else { echo false; } 
}
 
     
    