//ajax function
function initRequest(url) {
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        isIE = true;
        req = new ActiveXObject("Microsoft.XMLHTTP");
    }
}

// response from ajax
function processResponse() {
    if (req.readyState == 4) {
      if (req.status == 200) {
          var result = req.responseText;
          eval (result);
        }
    }  
}

function calculate(){
	//get values
	mainOptions = document.getElementById("mainOptions").value;
	printOptions = document.getElementById("printOptions").value;
	packingOptions = document.getElementById("packingOptions").value;
	quantity = document.getElementById("quantity").value;
	
  var urlgo = "cd_dvds_calculator_ajax.php?mainOptions="+mainOptions+"&printOptions="+printOptions+"&packingOptions="+packingOptions+
  "&quantity="+quantity;
  
  initRequest(urlgo);
  req.onreadystatechange = processResponse;
  req.open("GET", urlgo, true); 
  req.send(null);
}

function clean(){
	document.getElementById('netprice').innerHTML = ' ---';
	document.getElementById('vat').innerHTML = ' ---';
	document.getElementById('total').innerHTML = '£ ---';
}

function order() {
	location.href='user/session_builder.php?cd&quantity=' + document.getElementById("quantity").value + '&main=' + document.getElementById("mainOptions").value + '&print=' + document.getElementById("printOptions").value + '&packing=' + document.getElementById("packingOptions").value;
}