//var reEmail = /\b(^(\S+@)([a-zA-Z0-9\-]+\.)+(com|net|edu|mil|gov|org|int|([a-zA-Z]{2}))$)\b/gi
var reEmail = /^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$/;
var reInteger = /^\d+$/;

function isEmpty(s) {return ((s == null) || (s.length == 0))}
function isEmail(s) {return reEmail.test(s);}
function isInteger(s) {return reInteger.test(s);}

function isChecked(obj) {
	multi = true;
	if (obj.type == 'radio' || obj.type == 'checkbox') multi = false;
	var checked = false;
	if (multi) {
	   	for (var i = 0; i < obj.length; i++)
	   		if (obj[i].checked) {checked = true; break}
	}
	else checked = obj.checked;
	return checked;
}

function check_input(){

check = document.myform;
field = check.f_name;
if (isEmpty(field.value)) {alert("Podaj imię i nazwisko (ew. dane firmy)"); field.focus(); field.select(); return false;};
field = check.f_www;
if (isEmpty(field.value)) {alert("Podaj adres swojej strony www"); field.focus(); field.select(); return false;};
field = check.f_email;
if (isEmpty(field.value) || !isEmail(field.value)) {alert("Nieprawidłowy adres email"); field.focus(); field.select(); return false;};
field = check.f_confirm;
if (!isChecked(field)) {alert("Musisz zaakceptować Regulamin Współpracy"); return false;};

return true;
}