function validateSubscriber() {
	var namesub = document.getElementById('namesub').value;
	
	if(!/^[a-zA-Z]+$/i.test(namesub))
	{
		alert('First name is invalid.');
		return false;
	}
	
	var lastnamesub = document.getElementById('lastnamesub').value;
	
	if(!/^[a-zA-Z]+$/i.test(lastnamesub))
	{
		alert('Last name is invalid.');
		return false;
	}
	
	var emailsub = document.getElementById('emailsub').value;
	
	if(!/^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.){1,2}([a-z]{2,4})$/i.test(emailsub))
	{
		alert('E-mail is invalid.');
		return false;
	}
}