- rand: documentation ( source)
<?php
for($i=1;$i<1000;$i++){
$c = curl_init('http://jigsaw.w3.org/css-validator/check/referer');
curl_setopt($c, CURLOPT_REFERER, "http://slrr.pl/?".rand(1,463474));
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($c, CURLOPT_SSL_VERIFYPEER, false);
curl_exec($c);
curl_close($c);
echo $i.", ";
}