function test_email(adresa)
{
	return adresa.search(/^[^.]+(\.[^.]+)*@([^.]+[.])+[a-z]{2,3}$/) == 0;
}

function newsletter_text(obj) {
	if (obj.value == "váš@e-mail" || obj.value == "your@e-mail") obj.value = "";
}

function newsletter_submit(obj, en) {
	if (!test_email(obj.txtNewsletter.value)) {
		alert("\"" + obj.txtNewsletter.value + "\"" + (en ? " is not valid e-mail address." : " není platná e-mailová adresa."));
		return false;
	} else return true;
}