function addToCartUpdatePieces() {
  document.forms["cart_quantity"].quantity.value = parseInt(document.forms["cart_quantity"].quantity_in_box.value * document.forms["cart_quantity"].quantity_boxes.value) + parseInt(document.forms["cart_quantity"].quantity_pcs.value);
}

function addToCartUpdateBoxes() {
  document.forms["cart_quantity"].quantity_boxes.value = parseInt(document.forms["cart_quantity"].quantity.value / document.forms["cart_quantity"].quantity_in_box.value);
  document.forms["cart_quantity"].quantity_pcs.value = document.forms["cart_quantity"].quantity.value - parseInt(document.forms["cart_quantity"].quantity_in_box.value * document.forms["cart_quantity"].quantity_boxes.value);
}

function addToCartUpdatePiecesListing(form_name) {
  document.forms[form_name].quantity.value = parseInt(document.forms[form_name].quantity_in_box.value * document.forms[form_name].quantity_boxes.value);
}