function isEmailAddress (string) {
  var addressPattern = 
    /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/;
  return addressPattern.test(string);
}

function isTel (string) {
  var addressPattern = 
  /^([0]\d{2}(-|\s)[1-9]\d{6})|([0]\d{3}(-|\s)[1-9]\d{5})|([0]\d{9})$/;
  return addressPattern.test(string);
}

function isPostcode (string) {
  var addressPattern = 
     /^\d{4}\s?[A-Za-z]{2}$/;
  return addressPattern.test(string);
}

function isNum (string) {
  var addressPattern =  /^\d+$/;
  return addressPattern.test(string);
}

function submitform() {
  var submitdata = true
  var errorstr = ""
  
  errorstr = "De volgende gegevens ontbreken of zijn niet compleet :\n";
  
    if (document.contact.company.value.length==0)
     {
       errorstr = errorstr + "\n" + "  - Company";
       submitdata = false;
     }  
    if ( ( document.contact.gender[0].checked!=1 ) &&
       ( document.contact.gender[1].checked!=1 ))
     {
       errorstr = errorstr + "\n" + "  - Gender";
       submitdata = false;
     }  

  if (document.contact.name.value.length==0)
     {
       errorstr = errorstr + "\n" + "  - Name";
       submitdata = false;
     }
	 
  if (document.contact.telephonenumber.value.length==0)
   	{
		errorstr = errorstr + "\n" + "  - Telephone number";
		submitdata = false;
    } 

	
  if (!isEmailAddress(document.contact.email.value))
     {
       errorstr = errorstr + "\n" + "  - E-mailadres incorrect";
       submitdata = false;
     } 

	if ( ( document.contact.more_information_about[0].checked!=1 ) &&
       ( document.contact.more_information_about[1].checked!=1 ) &&
	   ( document.contact.more_information_about[2].checked!=1 ))
     {
       errorstr = errorstr + "\n" + "  - Information about";
       submitdata = false;
     }  

	 
  if (submitdata==true)
   {
     document.contact.action="contact_quota_submit.php";
     document.contact.submit();
   }
   else
   {
     alert(errorstr);
   }
}