1.原理
数组中每个图片对应一个值->随机值->获取并保存到$_SESSION中，->获取随机值对应的图片，->通过__FILE__输出图片，->浏览器验证
2.代码
captcha.php
<?php
session_start();
//图片对应
$picArray = array(
‘pic00‘=>‘狗‘,
‘pic01‘=>‘猫‘,
‘pic02‘=>‘鱼‘,
‘pic03‘=>‘鸟‘
);
//随机取值
$index = mt_rand(0,3);
$value = $picArray[‘pic0‘.$index];
$_SESSION[‘authcode‘] = $value;
$filename = dirname(__FILE__).‘./img/pic0‘.$index.‘.jpg‘;
//echo $filename;
$content = file_get_contents($filename);
header(‘Content-type: image/jpg‘);
echo $content;
form.php
<?php
if (isset($_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="captcha.php?r=<?php echo mt_rand() ?>" id="captcha_img" alt="验证码" width="200" height="200" border="1px"></p>
<a href="javascript:void(0)" onclick="document.getElementById(‘captcha_img‘).src=‘./captcha.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>
时间： 2024-12-11 18:32:45