function checkForm(){
	email = document.getElementById('contact_form_email').value;
	if(email==""||email==null){
		alert('Please enter an emailadres');
		return false;
	}
}

function change_image(targ){
	document.getElementById('product_largeimage').setAttribute('src',targ);
	return false;
}

function GetXmlHttpObject()
{
if (window.XMLHttpRequest)
  {
  // code for IE7+, Firefox, Chrome, Opera, Safari
  return new XMLHttpRequest();
  }
if (window.ActiveXObject)
  {
  // code for IE6, IE5
  return new ActiveXObject("Microsoft.XMLHTTP");
  }
return null;
}

function getUrinals(){
	xmlhttp=GetXmlHttpObject();
	if (xmlhttp===null){
		alert ("Browser does not support HTTP Request");
		return;
	}
	var url="calculator.php";
	
	var params = '?visitors=' + document.getElementById('calculator_visitors').value;
	params = params + '&hours=' + document.getElementById('calculator_hours').value;
	params = params + '&alcohol=' + document.getElementById('calculator_alcohol').checked;
	params = params + '&timestamp=' + (new Date()).getDate();

	url = url + params;
	
	xmlhttp.open("GET",url,true);
	xmlhttp.send(null);
	
	xmlhttp.onreadystatechange=function(){
		if (xmlhttp.readyState == 4 && xmlhttp.status == 200){
			document.getElementById('calculator_result').innerHTML = xmlhttp.responseText;
		}
	}
}