function validate(f) {
 	var mail = f.f_mail.value;
	var m_wr = /^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/;
	
	if (f.f_name.value == "") {
	 	alert("Please, fill the name box");
        f.f_name.focus();
        f.f_name.select();
		return false;
	}
	else if (f.f_country.value == "") {
		alert("Please, choose your country of residence");
        f.f_country.focus();
		return false;
	}	 	
	else if (!mail.match(m_wr)) {
	 	alert("Please, check your E-mail address");
		f.f_mail.focus();
		f.f_mail.select();
		return false;
	}	  
	return true;
} 
function check_agreement(b){
	document.getElementById('submit').disabled =! b.checked;
}