Php generate random numbers

/*random function
$length: length of needed number
*/
function random($length) {
$hash = ”;
$chars = ‘0123456789′;
$max = strlen($chars) – 1;
mt_srand((double)microtime() * 1000000);
for($i = 0; $i < $length; $i++) { $hash .= $chars[mt_rand(0, $max)]; }
return $hash;
}

echo random(8);