function checkEmail(email)
{
  regexp = /\w+([\.\-_]{1}\w+)*@(\w+([\.\-_]{1}\w+)*)\.(\w{2,4})/;

  test = ("" + email).match(regexp);
  if (email.length < 6) return false;
  if(test && typeof test[0] != "undefined") test = test[0];
  return (test==email || ("" + email)=="");
}

function addEmail(paramSource)
{
	var emailAdressen = document.mailafriend.emaillijst.length;
	var stremail = document.mailafriend.femail.value;
	if (!checkEmail(stremail)) {
		if(String(paramSource) != "messenger") {
			alert("Het opgegeven e-mailadres is incorrect!");
		}
	} else {
		if(emailAdressen > 0) {
			var bAllowTip = true;
			for(var i=0; i<emailAdressen; i++) {
				if(stremail == document.mailafriend.emaillijst.options[i].value) {
					alert("Het e-mailadres \"" + stremail + "\" staat al in de lijst!");
					bAllowTip = false;
					return false;
				}
			}
			if(bAllowTip) {
				document.mailafriend.emaillijst.options[emailAdressen] = new Option(stremail, stremail);
				document.mailafriend.femail.value = "";
				document.mailafriend.femail.focus();
			}
		} else {
			document.mailafriend.emaillijst.options[emailAdressen] = new Option(stremail, stremail);
			document.mailafriend.femail.value = "";
			document.mailafriend.femail.focus();
			return false;
		}
	}
}

function addMSN()
{
  window.open("msn.php","","top=100,left=100,width=600,height=500,scrollbars=1");
}

function submitEmail()
{
  var adressen = '';
	for(var i=0; i<document.mailafriend.emaillijst.length; i++)
	{
		adressen += document.mailafriend.emaillijst.options[i].value + ",";
	}
	adressen = adressen.substring(0,adressen.lastIndexOf(","));
	document.mailafriend.adressen.value = adressen;
	document.forms[mailafriend].submit();
}