captcha vendetta

<?php
$aant       = "2";//this varable can be 2-40
$height     = "35";
$SQUARE     = "1"; //this varable can be 1 = ON, 0 = OFF
$possible   = 'abdefghjkmnpqrstuvwxyz23456789'; //Characters used in code
$Background = "AUTO"; // this varible can be AUTO, WHITE, RED, GREEN, BLUE
$LINES      = "0"; //Draw lines?  this varable can be 1 = ON, 0 = OFF
$LINES_OVER = "0"; //Draw lines Over text? this varable can be 1 = ON, 0 = OFF
//Start de sessie
session_start();
 
  function generateCode($characters,$possible) {
 
      $code = '';
      $i = 0;
      while ($i < $characters) { 
         $code[] = substr($possible, mt_rand(0, strlen($possible)-1), 1);
         $codestr.=substr($possible, mt_rand(0, strlen($possible)-1), 1);
         $i++;
      }
      return $code;
   }
 
// Maak 't plaatje
$width= $aant * 35;
$im = imagecreate($width, $height);
 
//Achtergrond kleur
$Background = strtoupper ($Background);
if ($Background=="AUTO"){
$bg = imagecolorallocate($im, rand(190,255), rand(190,255), rand(190,255));
}elseif($Background=="WHITE"){
$bg = imagecolorallocate($im, 255, 255, 255);
}elseif($Background=="RED"){
$bg = imagecolorallocate($im, 255 , 0, 0);
}elseif($Background=="GREEN"){
$bg = imagecolorallocate($im, 0, 255, 0);
}elseif($Background=="BLUE"){
$bg = imagecolorallocate($im, 0, 0, 255);
}else{
$bg = imagecolorallocate($im, 255, 255, 255);
}
 
// Genereer de code
$code= generateCode($aant,$possible);
 
if($LINES=="0" ){
// Teken variabele lijnen
$i=0;
while( $i<($width*$height)/150) {
    $noise_color = imagecolorallocate($im, rand(250,255), rand(150,255), rand(150,255));
    imageline($im, rand(0,$width), rand(0,$height), rand(0,$width), rand(0,$height), $noise_color);
          $i++;
}
}
 
if($SQUARE=="1" ){
// Teken een vierkand van 2 punten
$vierkand = imagecolorallocate($im, rand(0,155), rand(0,255), rand(0,255));
imageline($im, 0, 0, $width, 0, $vierkand);
imageline($im, 0, 1, $width, 1, $vierkand);
imageline($im, $width-1, 0, $width-1, $height, $vierkand);
imageline($im, $width-2, 0, $width-2, $height, $vierkand);
imageline($im, $width-1, $height-1, 0, $height-1, $vierkand);
imageline($im, $width-1, $height-2, 0, $height-2, $vierkand);
imageline($im, 0, $height, 0, 0, $vierkand);
imageline($im, 1, $height, 1, 0, $vierkand);
}
 
$widthpercar= 35;
//zorg er voor dat de text niet over elkaar gaat staan
$i = 0;
      while ($i < $aant) { 
          $min=($widthpercar*$i) - 1;
          $max=$widthpercar*$i;
          $textcolor = imagecolorallocate($im, rand(0,150), rand(0,150), rand(0,150));
if ($i == 0){
imagestring($im, 28, rand(0,$widthpercar), rand(0,$height-14), $code[$i], $textcolor);
}elseif ($i==$aant){
imagestring($im, 28, rand($min+8,$max), rand(0,$height-14), $code[$i], $textcolor);
}else{
imagestring($im, 28, rand($min+8,$max), rand(0,$height-14), $code[$i], $textcolor);
}
$codestr = $codestr . $code[$i];
$i++;
}
 
 
if($LINES_OVER=="1" ){
// teken voor de zekerheid nog ff 2 lijnen OVER de text
$i=0;
while( $i<2) {
     $noise_color = imagecolorallocate($im, rand(230,255), rand(230,255), rand(230,255));
         imageline($im, rand(0,$width), rand(0,$height), rand(0,$width), rand(0,$height), $noise_color);
          $i++;
}
}
 
$_SESSION['verify']=$codestr;
// Print het plaatje
header("Content-type: image/png");
imagepng($im);
imagedestroy($im);
 
?>
<script language="JavaScript1.2">
var sec = 31;


function countDown() {
  sec--;
  if (sec == 00) {
    window.location.reload( false );
  }
if (sec<=9) { sec = "0" + sec; }
  time =  sec + " seconden ";
if (document.getElementById) { theTime.innerHTML = time; }
  SD=window.setTimeout("countDown();", 1000);
}


function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    
    }
  }
}


addLoadEvent(function() {
  countDown();
});


     </script>