function validate_email(field,alerttxt)
{
with (field)
  {
  apos=value.indexOf("@");
  dotpos=value.lastIndexOf(".");
  if (apos<1||dotpos-apos<2)
    {alert(alerttxt);return false;}
  else {return true;}
  }
}


function validate_required(field,alerttxt)
{
with (field)
  {
  if (value==null||value=="")
    {
    alert(alerttxt);return false;
    }
  else
    {
    return true;
    }
  }
}

function validate_form(thisform)
{

with (thisform)
  {
  if (validate_required(achternaam,"<?=$error_achternaam?>")==false)
  {achternaam.focus();return false;}
  if (validate_required(inits,"<?=$error_init?>")==false)
  {inits.focus();return false;}
  if (validate_required(adres,"<?=$error_adres?>")==false)
  {adres.focus();return false;}
  if (validate_required(postc,"<?=$error_zip?>")==false)
  {postc.focus();return false;}
  if (validate_required(woon,"<?=$error_city?>")==false)
  {woon.focus();return false;}
  if (validate_email(email,"<?=$error_email?>")==false)
  {email.focus();return false;}
  }
  
	process_type = -1;
	for (i=thisform.process_type.length-1; i > -1; i--) {
		if (thisform.process_type[i].checked) {
		process_type = i; i = -1;
		}
	}
	
	if (process_type == -1) {
		alert("<?=$error_payment?>");return false;
	}
	
var AV = document.getElementById('AV_check');
if(!AV.checked) {
		alert("<?=$error_AV?>");return false; }
}