- session_start();
- //随机生成验证码的字符串
- function random($len) {
- $srcstr="ABCDEFGHIJKLMNPQRSTUVWXYZ123456789";
- mt_srand();
- $strs="";
- for($i=0;$i $strs.=$srcstr[mt_rand(0,33)];
- }
- return ($strs);
- }
- $str=random(5); //随机生成的字符串
- $width=60; //验证码图片的宽度
- $height=25; //验证码图片的高度
- //Date in the past
- header("Expires:Mon,26 Jul 1997 05:00:00 GMT");
- //always modified
- header("Last-Modified:".gmdate("D,d M Y H:i:s")."GMT");
- //HTTP/1.1
- header("Cache-Control:no-store,no-cache,must-revalidate");
- header("Cache-Control:post-check=0,pre-check=0",false);
- //HTTP/1.0
- header("Pragma:no-cache");
- header("Content-Type:image/png");
-
- $im=imagecreate($width,$height);
- $back=imagecolorallocate($im,0xFF,0xFF,0xFF); //背景色
- $pix=imagecolorallocate($im,187,190,247); //模糊点颜色
- $font=imagecolorallocate($im,41,163,238); //字体色
- //绘制1000个模糊作用的点
- mt_srand();
- for($i=0;$i imagesetpixel($im,mt_rand(0,$width),mt_rand(0,$height),$pix);
- }
- imagestring($im,5,7,5,$str,$font);//绘制随机生成的字符串
- imagerectangle($im,0,0,$width-1,$height-1,$font);//在验证码图像周围绘制1px的边框
- imagepng($im);//建立一张PNG格式图形
- imagedestroy($im);//将图片handle解构，释于内存空间
- $_SESSION["auth_code"]=$str;
- ?>
例2，php随机验证码
php生成简单的验证码
- $image_width=140;
- $image_height=50;
- srand(microtime()*10000);
- for($i=0;$i $number.=dechex(rand(0,15));
- }
- $check=$number;
- $im=imagecreate($image_width,$image_height);
- imagecolorallocate($im,255,255,255);
- for($i=0;$i $font=rand(40,80);
- $x=rand(1,8)+$image_width*$i/4;
- $y=rand(1,$image_height/4);
- $color=imagecolorallocate($im,rand(0,100),rand(0,150),rand(0,200));
- imagestring($im,$font,$x,$y,$check[$i],$color);
- }
- imagepng($im);
- imagedestroy($im);
- ?>
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