php 字母和数字验证码

时间：2023-03-09 21:21:41
php 字母和数字验证码

//验证码

<?php

//实现简单的验证码

//session_start

session_start();

//画布

$image = imagecreatetruecolor(100, 30);

//设置填充颜色

$bgcolor = imagecolorallocate($image, 255, 255, 255);

//填充

imagefill($image, 0, 0, $bgcolor);

//随机数据

//session

$captcha_code = '';

for ($i = 0; $i < 4; $i++) {

    $fontsize = 5;

    $fontcolor = imagecolorallocate($image, mt_rand(0, 120), mt_rand(0, 120), mt_rand(0, 120));

    $data = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';

//    echo strlen($data);

//    echo substr($data,61,1);

    $font = substr($data, mt_rand(0, strlen($data) - 1), 1);

    $captcha_code .= $font;

    $width = ($i * 100) / 4 + mt_rand(5, 10);

    $height = mt_rand(5, 10);

    //添加

    imagestring($image, $fontsize, $width, $height, $font, $fontcolor);

}

//保存到session

$_SESSION['authcode'] = $captcha_code;

//干扰

//像素点

for ($i = 0; $i < 200; $i++) {

    $pixcolor = imagecolorallocate($image, mt_rand(20, 200), mt_rand(20, 200), mt_rand(20, 200));

    imagesetpixel($image, mt_rand(0, 99), mt_rand(0, 29), $pixcolor);

}

//线

for ($i = 0; $i < 4; $i++) {

    $linecolor = imagecolorallocate($image, mt_rand(50, 220), mt_rand(50, 220), mt_rand(50, 220));

    imageline($image, mt_rand(0, 99), mt_rand(0, 29), mt_rand(0, 99), mt_rand(0, 99), $linecolor);

}

//输出

header('Content-type: image/png');

imagepng($image);

//销毁

imagedestroy($image);

//验证表单

<?php

if (isset($_REQUEST['authcode'])) {

    session_start();

    //判断

    if (strtolower($_REQUEST['authcode'] == strtolower($_SESSION['authcode']))) {

        echo '恭喜你输入正确！';

    } else {

        echo '输入失败！';

    }

    exit();

}

?>

<html>

<head>

    <title>验证码提交</title>

</head>

<body>

<form action="./form.php" method="post">

    <p>验证码：<img src="./code01.php" id="captcha_img" alt="验证码" width="100" height="30" border="1px"></p>

    <a href="javascript:void(0)" onclick="document.getElementById('captcha_img').src='./code01.php?r='+Math.random()">看不清?</a>

    <p>

        <label for="authcode">请输入图片中的内容: </label>

        <input type="text" name="authcode" id="authcode"/>

    </p>

    <p><input type="submit" value="submit"/></p>

</form>

</body>

</html>

相关文章