function shipping_calc() {

var x = document.getElementById('shipping-zone').value;
var y = document.getElementById('quantity').value;

  if ((x == "Ireland") && (y =="3")) {
     document.getElementById('shipping').value = "9.90";
  } else {
     // do nothing
  }

  if ((x == "Ireland") && (y =="2")) {
     document.getElementById('shipping').value = "8.00";
  } else {
     // do nothing
  }

  if ((x == "Ireland") && (y =="1")) {
     document.getElementById('shipping').value = "3.85";
  } else {
     // do nothing
  }

  if ((x == "Europe") && (y =="3")) {
     document.getElementById('shipping').value = "12.90";
  } else {
     // do nothing
  }

  if ((x == "Europe") && (y =="2")) {
     document.getElementById('shipping').value = "9.50";
  } else {
     // do nothing
  }

  if ((x == "Europe") && (y =="1")) {
     document.getElementById('shipping').value = "5.85";
  } else {
     // do nothing
  }

  if ((x == "World") && (y =="3")) {
     document.getElementById('shipping').value = "18.90";
  } else {
     // do nothing
  }

  if ((x == "World") && (y =="2")) {
     document.getElementById('shipping').value = "12.50";
  } else {
     // do nothing
  }

  if ((x == "World") && (y =="1")) {
     document.getElementById('shipping').value = "5.85";
  } else {
     // do nothing
  }

}