function str_trim(str)
{
	str = str.replace(/^\s*/g,'');
	str = str.replace(/\s*$/g,'');
	return str;
}

function tell_a_friend(email,response_object,invalid_email_msg,positive_msg,negative_msg)
{
	email = str_trim(email);
	check_str = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	is_ok = check_str.test(email);
	if (is_ok)
	{
		ajax_obj = create_ajax_object();
		ajax_obj.onreadystatechange = function ()
		{
			if (ajax_obj.readyState == 4)
			{
				if (ajax_obj.status == 200)
				{
					response = parseInt(ajax_obj.responseText);
					response_object.innerHTML = response?positive_msg:negative_msg;
				}
				else
				{
					
				}
			}
		};
		
		ajax_obj.open('GET','./bzr_tell_a_friend.php?email='+email,true);
		ajax_obj.send(null);
	}
	else
	{
		alert(invalid_email_msg)
	}
}