function checkInput()
{
missinginfo = "";
	if (document.tip.Naam.value == "") {missinginfo = "\n - Uw Naam";t='Naam';
	return check();}

	if (document.tip.Adres.value == "") {missinginfo = "\n - Adres";t='Adres';
	return check();}

	if (document.tip.Postcode.value == "") {missinginfo = "\n - Postcode";t='Postcode';
	return check();}

	if (document.tip.Plaats.value == "") {missinginfo = "\n - Plaats";t='Plaats';
	return check();}

	if (document.tip.Telefoon.value == "") {missinginfo = "\n - Telefoon";t='Telefoon';
	return check();}

	if (document.tip.Email.value == "") {missinginfo = "\n - Email adres";t='Email';
	return check();}

}

function check()
{
	if (missinginfo != "") 
	{
	missinginfo ="s.v.p. invullen:" +
	missinginfo;
	alert(missinginfo);
	document.tip.elements[t].focus();
	return false;
	}
	else return true;
}