function CheckEmail(email)
{
var test = /^[_.0-9A-Za-z-]+@([0-9A-Za-z][0-9A-Za-z-]+.)+[A-Za-z]{2,4}$/;
var result = email.match(test);

if (result == null)
{
alert("Niepoprawny adres e-mail");
return false;
}

return true;
}