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_form(thisform){
	with (thisform){
		if (validate_email(email,"U heeft geen geldig email adres ingevuld.")==false){
			email.focus();return false;
		}
	}
}