PHP图片验证码原代码，需支持gd2.dll扩展，需修改PHP.ini后重启IIS or apache
调用方法<img src="this.php">
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程序代码:
<?PHPsession_start();session_register('SafeCode');$type = 'gif';$width= 40;$height= 16;header("Content-type: image/".$type);srand((double)microtime()*1000000);$randval = randStr(4,"");if($type!='gif' && function_exists('imagecreatetruecolor')){$im = @imagecreatetruecolor($width,$height);}else{$im = @imagecreate($width,$height);}$r = Array(225,211,255,223);$g = Array(225,236,237,215);$b = Array(225,236,166,125);$key = rand(0,3);$backColor = ImageColorAllocate($im,$r[$key],$g[$key],$b[$key]);//背景色（随机）$borderColor = ImageColorAllocate($im, 0, 0, 0);//边框色$pointColor = ImageColorAllocate($im, 255, 170, 255);//点颜色@imagefilledrectangle($im, 0, 0, $width - 1, $height - 1, $backColor);//背景位置@imagerectangle($im, 0, 0, $width-1, $height-1, $borderColor); //边框位置$stringColor = ImageColorAllocate($im, 255,51,153);for($i=0;$i<=100;$i++){$pointX = rand(2,$width-2);$pointY = rand(2,$height-2);@imagesetpixel($im, $pointX, $pointY, $pointColor);}@imagestring($im, 3, 5, 1, $randval, $stringColor);$ImageFun='Image'.$type;$ImageFun($im);@ImageDestroy($im);$_SESSION['SafeCode'] = $randval;//产生随机字符串function randStr($len=6,$format='ALL') {switch($format) {case 'ALL':$chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; break;case 'CHAR':$chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'; break;case 'NUMBER':$chars='0123456789'; break;default :$chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';break;}$string="";while(strlen($string)<$len)$string.=substr($chars,(mt_rand()%strlen($chars)),1);return $string;}?>
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<?php// BY PHP 国度 www.phphot.be//关闭报错error_reporting(0);//图片宽度$x_size=60;//图片高度$y_size=20;//生成4个随机字符$nmsg=num_rand(4);//支持安全通连接吗?$S=$_SERVER['SERVER_PORT']=='443' ? 1:0;//使用cookie记录随机码//expire=0 cookie将会在会话结束后（一般是浏览器关闭）失效。setCookie('ck_num',md5($nmsg),0,'/','',$S);//创建宽:60*20的图片(画布)$aimg = imagecreate($x_size,$y_size);//设置图片背景色$back = imagecolorallocate($aimg, 255, 255, 255);//设置字体颜色$border = imagecolorallocate($aimg, 0, 0, 0);//从0,0点填充59*19的白色矩形区域imagefilledrectangle($aimg, 0, 0, $x_size - 1, $y_size - 1, $back);//从0,0点绘制59*19的黑色矩形边框imagerectangle($aimg, 0, 0, $x_size - 1, $y_size - 1, $border);for ($i=0;$i<strlen($nmsg);$i++){ //在图片上写字 imageString($aimg,5,$i*$x_size/4+3,2, $nmsg[$i],$border);}header("Content-type: image/png");imagepng($aimg);imagedestroy($aimg);exit;function num_rand($lenth){ // 播下一个随机数发生器种子 //php自4.2.0起,，此参数变为可选项，当该项为空时，会被设为随时数 mt_srand((double)microtime() * 1000000); //产生有4个随机数字的字符串 for($i=0;$i<$lenth;$i++){ $randval.= mt_rand(0,9); } //对含有4个数字的字符串使用md5加密,长度是32位的 //从3长度为32的字符中,自最小数起或最大数32-$lenth起,取长度为$lenth的字符串 $randval=substr(md5($randval),mt_rand(0,32-$lenth),$lenth); return $randval;}?>
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