php 实现验证码确认
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作者:huidong
| 分類:【編程】php
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index.php
<?php session_start(); if (isset($_REQUEST['authcode'])) { if (strtolower($_REQUEST['authcode']) == $_SESSION['captcha_code']) { echo '<font color ="#0000CC"> 输出正确</font>'; # code... } else { echo $_REQUEST['authcode']; echo $_SESSION['authcode']; echo '<font color ="#CC0000"> 输出错误</font>'; } exit(); } ?> <!DOCTYPE html> <html> <head> <meta charset="gbk" /> <title>验证码测试</title> </head> <body> <form method="post"> <p> 验证码图片: <img id="captcha_img" border="1" src="./captcha_image.php" alt="验证码" /> <!-- 点击后修改图片链接的随机数参数,迫使图片刷新(否则浏览器会依靠缓存内容而不刷新) --> <a href="javascript:void(0)" onclick="document.getElementById('captcha_img').src='./captcha_image.php?r=' + Math.random() ">换一个</a> </p> <p> 请输入图片中的内容: <input type="text" name="authcode" value="" /> </p> <p> <input type="submit" value="提交" style="padding: 6px 20px;" /> </p> </form> </body> </html>
captcha_image.php
<?php /** * captcha_image.php * 每次加载此页面将显示不同的验证码图像,并自动更新 $_SESSION["captcha_code"] * * 代码来自:https://blog.csdn.net/chenfang0529/article/details/81295479 * (huidong 对源码进行了修订和整合) * * 使用方法: * 只需在 HTML 中使用 img 标签展示此页面的图片即可,例如: * <img id="captcha_img" border="1" src="./captcha_image.php" alt="验证码" /> * <!-- 点击后修改图片链接的随机数参数,迫使图片刷新(否则浏览器会依靠缓存内容而不刷新)--> * <a href="javascript:void(0)" onclick="document.getElementById('captcha_img').src='./captcha_image.php?r=' + Math.random() ">换一个</a> * * 创建时间:2024.6.14 */ session_start(); // 获取随机验证码并存储到 session 中,然后绘制出来 $code = GetRandomCode(); $_SESSION["captcha_code"] = $code; DrawCaptchaCode($code); /**** 以下是函数实现 ****/ // 得到随机验证码 // $len 验证码长度 // $data 验证码字典 // 返回值为生成的随机验证码 function GetRandomCode($len = 4, $data = 'abcdefghijkmnpqrstuvwxy3456789') { $code = ""; for ($i = 0; $i < $len; $i++) { $code .= substr($data, rand(0, strlen($data) - 1), 1); } return $code; } // 绘制验证码到网页 // 大小:100px * 30px // $captcha_code 验证码内容 function DrawCaptchaCode($captcha_code) { // 创建 100px * 30px 的画布对象 $image = imagecreatetruecolor(100, 30); // 填充背景 $bgcolor = imagecolorallocate($image, rand(200, 255), rand(200, 255), rand(200, 255)); imagefill($image, 0, 0, $bgcolor); // 绘制文字 for ($i = 0; $i < strlen($captcha_code); $i++) { $fontsize = 5; $fontcolor = imagecolorallocate($image, rand(0, 120), rand(0, 120), rand(0, 120)); $fontcontent = substr($captcha_code, $i, 1); $x = ($i * 100 / 4) + rand(5, 10); $y = rand(5, 12); imagestring($image, $fontsize, $x, $y, $fontcontent, $fontcolor); } // 噪点 for ($i = 0; $i < 200; $i++) { // 选取随机颜色 $pointcolor = imagecolorallocate($image, rand(50, 200), rand(50, 200), rand(50, 200)); // 绘制随机噪点 imagesetpixel($image, rand(1, 99), rand(1, 29), $pointcolor); } // 干扰线 for ($i = 0; $i < 5; $i++) { // 选取随机颜色 $linecolor = imagecolorallocate($image, rand(0, 255), rand(0, 255), rand(0, 255)); // 绘制随机直线 imageline($image, rand(1, 99), rand(1, 29), rand(1, 99), rand(1, 29), $linecolor); } // 输出图像文件 header('content-type:image/png'); imagepng($image); // 销毁画布对象 imagedestroy($image); } ?>
js 版本,做个记录。代码来自网络,使用 canvas 绘制。(原博客链接已丢失)
<!DOCTYPE html> <html> <!-- head --> <head> <title>图片登录验证</title> </head> <body> <input type="text" value="" placeholder="请输入验证码(区分大小写)" style="height:43px;position: relative; top:-15px; font-size:20px;"id ="text"> <canvas id="canvas" width="100" height="43" onclick="dj()" style="border: 1px solid #ccc; border-radius: 5px;"></canvas> <button class="btn" onclick="sublim()">提交</button> </body> <script> var show_num = []; draw(show_num); function dj() { draw(show_num); } function sublim() { var val=document.getElementById("text").value; var num = show_num.join(""); if(val=='') { alert('请输入验证码!'); } else if(val == num) { alert('提交成功!'); document.getElementById(".input-val").val(''); draw(show_num); } else { alert('验证码错误!\n你输入的是: '+val+"\n正确的是: "+num+'\n请重新输入!'); document.getElementById("text").value=''; draw(show_num); } } function draw(show_num) { var canvas_width=document.getElementById('canvas').clientWidth; var canvas_height=document.getElementById('canvas').clientHeight; var canvas = document.getElementById("canvas");//获取到canvas的对象,演员 var context = canvas.getContext("2d");//获取到canvas画图的环境,演员表演的舞台 canvas.width = canvas_width; canvas.height = canvas_height; var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0,q,w,e,r,t,y,u,i,o,p,a,s,d,f,g,h,j,k,l,z,x,c,v,b,n,m"; var aCode = sCode.split(","); var aLength = aCode.length;//获取到数组的长度 for (var i = 0; i <= 3; i++) { var j = Math.floor(Math.random() * aLength);//获取到随机的索引值 var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度 var txt = aCode[j];//得到随机的一个内容 show_num[i] = txt; var x = 10 + i * 20;//文字在canvas上的x坐标 var y = 20 + Math.random() * 8;//文字在canvas上的y坐标 context.font = "bold 23px 微软雅黑"; context.translate(x, y); context.rotate(deg); context.fillStyle = randomColor(); context.fillText(txt, 0, 0); context.rotate(-deg); context.translate(-x, -y); } // 验证码上显示线条 for (var i = 0; i <= 5; i++) { context.strokeStyle = randomColor(); context.beginPath(); context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height); context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height); context.stroke(); } // 验证码上显示小点 for (var i = 0; i <= 30; i++) { context.strokeStyle = randomColor(); context.beginPath(); var x = Math.random() * canvas_width; var y = Math.random() * canvas_height; context.moveTo(x, y); context.lineTo(x + 1, y + 1); context.stroke(); } } // 得到随机的颜色值 function randomColor() { var r = Math.floor(Math.random() * 256); var g = Math.floor(Math.random() * 256); var b = Math.floor(Math.random() * 256); return "rgb(" + r + "," + g + "," + b + ")"; } </script> </html>