PHP 生成英文单词验证码程序代码

具体

代码如下

复制代码

$width=145;
$height = 45;

$authcode = vcaptcha_read_code('words.txt') ;

$bg = 'bg/captcha_bg3.jpg';

$img_type   = 'png';

/* 验证码长度 */
$letters = strlen($authcode);

$img_bg    = (function_exists('imagecreatefromjpeg') && ((imagetypes() & IMG_JPG) > 0)) ?
                imagecreatefromjpeg($bg) : imagecreatefromgif($bg);
$bg_width = imagesx($img_bg);
$bg_height = imagesy($img_bg);

$img_org   = ((function_exists('imagecreatetruecolor')) && PHP_VERSION >= '4.3') ?
              imagecreatetruecolor($width, $height) : imagecreate($width, $height);

/* 将背景图象复制原始图象并调整大小 */
if (function_exists('imagecopyresampled') && PHP_VERSION >= '4.3') // GD 2.x
{
    imagecopyresampled($img_org, $img_bg, 0, 0, 0, 0, $width, $height, $bg_width, $bg_height);
}
else // GD 1.x
{
    imagecopyresized($img_org, $img_bg, 0, 0, 0, 0, $width, $height, $bg_width, $bg_height);
}
imagedestroy($img_bg);

$clr = imagecolorallocate($img_org, 255, 255, 255);

/* 绘制边框 */
imagerectangle($img_org, 0, 0, $width - 1, $height - 1, $clr);

/* 获得验证码的高度和宽度 */
$x = ($width - (imagefontwidth(5) * $letters)) / 2;
$y = ($height - imagefontheight(5)) / 2;
imagestring($img_org, 5, $x, $y, $authcode, $clr);

header('Expires: Thu, 01 Jan 1970 00:00:00 GMT');

// HTTP/1.1
header('Cache-Control: private, no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0, max-age=0', false);

// HTTP/1.0
header('Pragma: no-cache');
if ($img_type == 'jpeg' && function_exists('imagecreatefromjpeg'))
{
    header('Content-type: image/jpeg');
    imageinterlace($img_org, 1);
    imagejpeg($img_org, false, 95);
}
else
{
    header('Content-type: image/png');
    imagepng($img_org);
}

imagedestroy($img_org);

function vcaptcha_read_code($wordlist_file)
{
    $fp = @fopen($wordlist_file, 'rb');
    if (!$fp) return false;

    $fsize = filesize($wordlist_file);
    if ($fsize < 32) return false; // too small of a list to be effective

    if ($fsize < 128) {
        $max = $fsize; // still pretty small but changes the range of seeking
    } else {
        $max = 128;
    }

    fseek($fp, rand(0, $fsize - $max), SEEK_SET);
    $data = fread($fp, 128); // read a random 128 bytes from file
    fclose($fp);
    $data = preg_replace("/r?n/", "n", $data);

    $start = strpos($data, "n", rand(0, 100)) + 1; // random start position
    $end   = strpos($data, "n", $start);           // find end of word

    return strtolower(substr($data, $start, $end - $start)); // return substring in 128 bytes
}

使用方法:

代码如下

复制代码

将这段代码复制到HTML里，就可以了。还有这个的getCode函数是为了让用户看不清验证码，点击可以切换，JavaScript脚本如下:

http://file.zzzyk.com/upload/mbdown/pic/2013/06/26/13659538282901.txt 这是单词库大家可下载。

补充：Php教程,Php安全