function validateFormOnSubmit(theForm) {
	var reason = "";

	reason += validateEmpty(theForm.naam);
	reason += validateEmpty(theForm.telefoon);
	reason += validateEmail(theForm.email);
	reason += validateEmpty(theForm.straat);
	reason += validateEmpty(theForm.postcode);
	reason += validateEmpty(theForm.gemeente);

	if (reason != "") {
		
		alert("Niet alle velden werden correct ingevuld. Wij markeerden ze voor u in het rood");		
		return false;
	}else{

	return true;
}
}

function validateEmpty(fld) {
	var error = "";

	if (fld.value.length == 0) {
		fld.style.background = 'red';
		error = "Niet alle velden zijn ingevuld.\n"
	} else {
		fld.style.background = 'White';
	}
	return error;
}
function trim(s)
{
	return s.replace(/^\s+|\s+$/, '');
}

function validateEmail(fld) {
	var error="";
	var tfld = trim(fld.value);                        // value of field with whitespace trimmed off
	var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
	var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;

	if (fld.value == "") {
		fld.style.background = 'red';
		error = "Geen email-adres ingevuld.\n";
	} else if (!emailFilter.test(tfld)) {              //test email for illegal characters
		fld.style.background = 'red';
		error = "Geen geldig email-adres.\n";
	} else if (fld.value.match(illegalChars)) {
		fld.style.background = 'red';
		error = "Email-adres bevat niet toegelaten tekens.\n";
	} else {
		fld.style.background = 'White';
	}
	return error;
}