function spamcodecheck($idsession,$pass)
  {global $deltas;
    $ok=1;
    $code=$idsession;
    if ($idsession!="_id_") {
      $code=substr($code,2);
      $code=strrev($code);
      $code=substr($code,2);
      $code=$code+$deltas;
      if ($code==$pass) {
        $h=strrev(substr($idsession,0,2));
        $idsession=strrev($idsession);
        $m=substr($idsession,0,2);
        $date=getdate();
        $hour=$date[hours];
        $min=$date[minutes];
        if ($h==0) {$h=24;}
        if ($hour==0) {$hour=24;}
        $b=$h*60+$m;
        $e=$hour*60+$min;
        if ($e-$b<60) {$ok=0;}
      }
    }
    return $ok;

<?php
  $deltas = 500;
  $code=substr($code,2);
  $code=strrev($code);
  $code=substr($code,2);
  $code=$code+$deltas;
  if ($code==$deltas) {$code="err.";}
  $img = imagecreate(35,16);
  $bg = imagecolorallocate($img,255,255,255);
  $black = imagecolorallocate($img,0,0,0);
  imagestring($img,4,2,0,$code,$black);
  for ($i=0;$i<30;$i++) {
    $x=rand(2,34);
    $y=rand(2,15);
    imagesetpixel($img,$x,$y,$black);
  }
  header ("Content-type: image/jpeg");
  imagejpeg($img);
?>