function addAccessories(obj, price) {
    if(obj.checked == true) {
      document.getElementById('priceWithoutWat').value = parseInt(document.getElementById('priceWithoutWat').value) + price;
      document.getElementById('priceWithWat').value = Math.round(parseInt(document.getElementById('priceWithoutWat').value) * 1.2);
    } else {
      document.getElementById('priceWithoutWat').value = parseInt(document.getElementById('priceWithoutWat').value) - price;
      document.getElementById('priceWithWat').value = Math.round(parseInt(document.getElementById('priceWithoutWat').value) * 1.2);
    } 
}