php 中英文验证码程序

<script>ec(2);</script>

php 中英文验证码程序

$code="";      
for($i=0;$i    $Xi=mt_rand(0,strlen($str)/2);      
   if($Xi%2) $Xi+=1;      
   $code.=substr($str,$Xi,2);      
}      
$_SESSION['code']=$code;         //赋值给SESSION      
$im=imagecreatetruecolor($w,$h);      
$bkcolor=imagecolorallocate($im,250,250,250);      
imagefill($im,0,0,$bkcolor);      
/***添加干扰***/     
for($i=0;$i    $fontcolor=imagecolorallocate($im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));      
   imagearc($im,mt_rand(-10,$w),mt_rand(-10,$h),mt_rand(30,300),mt_rand(20,200),55,44,$fontcolor);      
}      
for($i=0;$i    $fontcolor=imagecolorallocate($im,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));      
   imagesetpixel($im,mt_rand(0,$w),mt_rand(0,$h),$fontcolor);      
}      
/***********内容*********/     
for($i=0;$i    $fontcolor=imagecolorallocate($im,mt_rand(0,120),mt_rand(0,120),mt_rand(0,120)); //这样保证随机出来的颜色较深。      
   $codex=iconv("GB2312","UTF-8",substr($code,$i*2,2));      
   imagettftext($im,mt_rand(20,24),mt_rand(-60,60),40*$i+20,mt_rand(30,35),$fontcolor,$fontface,$codex);      
}      
imagepng($im);
?>