Create a random password - PHP function

//a function that generates a random password

private function createRandomPassword()
{
	$chars = "abcdefghijkmnopqrstuvwxyz023456789";

	srand((double)microtime()*1000000);

	$i = 0;
	$pass = '' ;

	while ($i <= 7)
	{
		$num = rand() % 33;
		$tmp = substr($chars, $num, 1);
		$pass = $pass . $tmp;
		$i++;
	}

	return $pass;
}