function isValidEmail(str) 
{
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
}
function checkFields() 
{ //v4.0
  var error = "";
  name = document.contactform.naam.value;
  email = document.contactform.email.value;
  question = document.contactform.vraag.value;
  
  if (name == "" | name == "je naam")
  {
  	error += "naam is verplicht\n" ;
  }
  if (email == "" | email == "je e-mailadres")
  {
  	error += "e-mail is verplicht\n";
  }
  else if (!isValidEmail(email))
  {
	error += "Geen geldig e-mailadres\n";
  }
  if (question == "" | question == "typ hier je vraag")
  {
  	error += "vraag is verplicht";
  }
  
  if (error.length == 0)
	{
		return true;
	}
	else
	{
		alert (error);
		return false;
	}
}