function destroyDir($dir, $virtual = false)
{
	$ds = DIRECTORY_SEPARATOR;
	$dir = $virtual ? realpath($dir) : $dir;
	$dir = substr($dir, -1) == $ds ? substr($dir, 0, -1) : $dir;
	if (is_dir($dir) && $handle = opendir($dir))
	{
		while ($file = readdir($handle))
		{
			if ($file == '.' || $file == '..')
			{
				continue;
			}
			elseif (is_dir($dir.$ds.$file))
			{
				destroyDir($dir.$ds.$file);
			}
			else
			{
				unlink($dir.$ds.$file);
			}
		}
		closedir($handle);
		rmdir($dir);
		return true;
	}
	else
	{
		return false;
	}
}

function is_valid_email($email, $test_mx = false)
{
	if(eregi("^([_a-z0-9-]+)(\.[_a-z0-9-]+)*@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.[a-z]{2,4})$", $email))
		if($test_mx)
		{
			list($username, $domain) = split("@", $email);
			return getmxrr($domain, $mxrecords);
		}
		else
			return true;
	else
		return false;
}

Delete directory including all content

PHP