Problem get data from select, input-hidden value in Firefox

Problem get data from select, input-hidden value in Firefox

My code is:
  2. <div class="blockTxt">
  3. <input type="hidden"  name="item_type" value="<?php echo $r->cat;?>">
  4. <div class="foodName">
  5.   <h4 class="item_name"><?php echo $r->name;?></h4>
  6. </div>
  7. <div class="btnFood">
  8.    <select class="quantity-select">
  9.                <option selected="selected" value="8">8 </option>
  10.                <option value="16">16 </option>
  11.        <option value="24">24 </option>
  12.        </select>
  13. </div>
  14. <?php echo $r->cont; ?>
  15. </div>

  17. <button class="btn" data-id="<?php echo $r->id;?>">
  18.       Мake order
  19.      </button>

and JS-code:
  2. function addToCart(e){ 
  3.   ...........
  4.   var cartData = getCartData() || {}, 
  5.       parentBox = this.parentNode, 
  6.       itemId = this.getAttribute('data-id'), 
  7.       itemTitle = parentBox.querySelector('.blockTxt > .foodName > .item_name').innerHTML, 
  8.       itemPrice = parentBox.querySelector('.item-price').innerHTML,
  9.       itemQuant = parentBox.querySelector('.blockTxt > .btnFood > .quantity-select option:checked').value,
  10.       itemType  = parentBox.querySelector('.blockTxt input[name="item_type"]').value;
  11. ................................
  12. }
In Chrome browser it works, but in Firefox two last strings are not.
  2. itemQuant = parentBox.querySelector('.blockTxt > .btnFood > .quantity-select option:checked').value,
  3. itemType  = parentBox.querySelector('.blockTxt input[name="item_type"]').value;