- substr: documentation ( source)
- microtime: documentation ( source)
- explode: documentation ( source)
- dechex: documentation ( source)
- rand: documentation ( source)
<?php
$t = explode(' ', microtime());
$r = substr($t[1], 1) . rand(111111, 999999) . substr($t[0], 2, 6);
echo dechex($r);