Backend Development
PHP Tutorial
Teach you how to implement verification code in php, implement verification code in php_PHP tutorial
Teach you how to implement verification code in php, implement verification code in php_PHP tutorial
Teach you how to implement verification code in php, implement verification code in php
Verification codes are implemented more and more in forms, but verification codes written in js always feel unsatisfactory It’s convenient, so I learned the verification code implemented in PHP. Well, I actually had nothing to do, but I didn’t want to waste time, so I learned how to implement verification codes in PHP. As the saying goes, having too many skills does not weigh you down. Moreover, it can also be encapsulated into a function, which is very convenient for future use. Of course, it is not encapsulated now.
Now let’s talk about the simple purely numerical verification code.
If you are a beginner, it is recommended to follow the comments // numbers of my code step by step. The easiest way is to copy the entire code.
Create a new captcha.php:
php
//10>设置session,必须处于脚本最顶部
session_start();
$image = imagecreatetruecolor(100, 30); //1>设置验证码图片大小的函数
//5>设置验证码颜色 imagecolorallocate(int im, int red, int green, int blue);
$bgcolor = imagecolorallocate($image,255,255,255); //#ffffff
//6>区域填充 int imagefill(int im, int x, int y, int col) (x,y) 所在的区域着色,col 表示欲涂上的颜色
imagefill($image, 0, 0, $bgcolor);
//10>设置变量
$captcha_code = "";
//7>生成随机数字
for($i=0;$i<4;$i++){
//设置字体大小
$fontsize = 6;
//设置字体颜色，随机颜色
$fontcolor = imagecolorallocate($image, rand(0,120),rand(0,120), rand(0,120)); //0-120深颜色
//设置数字
$fontcontent = rand(0,9);
//10>.=连续定义变量
$captcha_code .= $fontcontent;
//设置坐标
$x = ($i*100/4)+rand(5,10);
$y = rand(5,10);
imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
//10>存到session
$_SESSION['authcode'] = $captcha_code;
//8>增加干扰元素，设置雪花点
for($i=0;$i<200;$i++){
//设置点的颜色，50-200颜色比数字浅，不干扰阅读
$pointcolor = imagecolorallocate($image,rand(50,200), rand(50,200), rand(50,200));
//imagesetpixel — 画一个单一像素
imagesetpixel($image, rand(1,99), rand(1,29), $pointcolor);
}
//9>增加干扰元素，设置横线
for($i=0;$i<4;$i++){
//设置线的颜色
$linecolor = imagecolorallocate($image,rand(80,220), rand(80,220),rand(80,220));
//设置线，两点一线
imageline($image,rand(1,99), rand(1,29),rand(1,99), rand(1,29),$linecolor);
}
//2>设置头部，image/png
header('Content-Type: image/png');
//3>imagepng() 建立png图形函数
imagepng($image);
//4>imagedestroy() 结束图形函数 销毁$image
imagedestroy($image);
Then comes the code for the static page: index.html
<doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>确认验证码title>
head>
<body>
<form method="post" action="./form.php">
<p>验证码: <img id="captcha_img" border='1' src='./captcha.php?r=echo rand(); ?>' style="width:100px; height:30px" />
<a href="javascript：void(0)" onclick="document.getElementById('captcha_img').src='./captcha.php?r='+Math.random()">换一个?a>
p>
<P>请输入验证码:<input type="text" name='authcode' value=''/>p>
<p><input type='submit' value='提交' style='padding:6px 5px;'/>p>
</body>
</html>
As you can see from index.html, the submitted form goes to form.php, so there is also a form.php code for judgment:
php
header("Content-Type:text/html;charset=utf-8"); //设置头部信息
//isset()检测变量是否设置
if(isset($_REQUEST['authcode'])){
session_start();
//strtolower()小写函数
if(strtolower($_REQUEST['authcode'])== $_SESSION['authcode']){
//跳转页面
echo "<script language=\"javascript\">";
echo "document.location=\"./form.php\"";
echo "</script>";
}else{
//提示以及跳转页面
echo "<script language=\"javascript\">";
echo "alert('输入错误!');";
echo "document.location=\"./form.php\"";
echo "</script>";
}
exit();
}
The page displayed is as follows:
Then, if pure numbers are implemented, it should not be difficult to add numbers and English. The code to be modified is just to change //7>Generate random numbers in captcha.php to //7>Generate random letters and numbers. If you are really cute, just modify these words and think it can be achieved, then Congratulations and stay happy forever. Brain-disabled children have a lot of fun.
No more nonsense, let’s pull the code.
php
//10>设置session,必须处于脚本最顶部
session_start();
$image = imagecreatetruecolor(100, 30); //1>设置验证码图片大小的函数
//5>设置验证码颜色 imagecolorallocate(int im, int red, int green, int blue);
$bgcolor = imagecolorallocate($image,255,255,255); //#ffffff
//6>区域填充 int imagefill(int im, int x, int y, int col) (x,y) 所在的区域着色,col 表示欲涂上的颜色
imagefill($image, 0, 0, $bgcolor);
//10>设置变量
$captcha_code = "";
//7>生成随机的字母和数字
for($i=0;$i<4;$i++){
//设置字体大小
$fontsize = 8;
//设置字体颜色，随机颜色
$fontcolor = imagecolorallocate($image, rand(0,120),rand(0,120), rand(0,120)); //0-120深颜色
//设置需要随机取的值,去掉容易出错的值如0和o
$data ='abcdefghigkmnpqrstuvwxy3456789';
//取出值，字符串截取方法 strlen获取字符串长度
$fontcontent = substr($data, rand(0,strlen($data)),1);
//10>.=连续定义变量
$captcha_code .= $fontcontent;
//设置坐标
$x = ($i*100/4)+rand(5,10);
$y = rand(5,10);
imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
//10>存到session
$_SESSION['authcode'] = $captcha_code;
//8>增加干扰元素，设置雪花点
for($i=0;$i<200;$i++){
//设置点的颜色，50-200颜色比数字浅，不干扰阅读
$pointcolor = imagecolorallocate($image,rand(50,200), rand(50,200), rand(50,200));
//imagesetpixel — 画一个单一像素
imagesetpixel($image, rand(1,99), rand(1,29), $pointcolor);
}
//9>增加干扰元素，设置横线
for($i=0;$i<4;$i++){
//设置线的颜色
$linecolor = imagecolorallocate($image,rand(80,220), rand(80,220),rand(80,220));
//设置线，两点一线
imageline($image,rand(1,99), rand(1,29),rand(1,99), rand(1,29),$linecolor);
}
//2>设置头部，image/png
header('Content-Type: image/png');
//3>imagepng() 建立png图形函数
imagepng($image);
//4>imagedestroy() 结束图形函数 销毁$image
imagedestroy($image);
The other two pages are not allowed to be modified.
Generally speaking, this is enough for now. But just like anime, there will always be extras.
So, let’s do a side story about Chinese characters. In fact, I am also planning to put the Chinese character verification code into my graduation project. Although sliding verification codes are very popular now, I am not specialized in learning js after all.
Moreover, you can also tell the defending teacher that our verification code does not require materials, even the pictures are generated, and there is nothing to pretend to be 13 with your own knowledge.
php
//11>设置session,必须处于脚本最顶部
session_start();
//1>设置验证码图片大小的函数
$image = imagecreatetruecolor(200, 60);
//5>设置验证码颜色 imagecolorallocate(int im, int red, int green, int blue);
$bgcolor = imagecolorallocate($image,255,255,255); //#ffffff
//6>区域填充 int imagefill(int im, int x, int y, int col) (x,y) 所在的区域着色,col 表示欲涂上的颜色
imagefill($image, 0, 0, $bgcolor);
//7>设置ttf字体
$fontface = 'FZYTK.TTF';
//7>设置字库，实现简单的数字储备
$str='天地不仁以万物为刍狗圣人不仁以百姓为刍狗这句经常出现在控诉暴君暴政上地残暴不仁把万物都当成低贱的猪狗来看待而那些高高在上的所谓圣人们也没两样还不是把我们老百姓也当成猪狗不如的东西但实在正取的解读是地不情感用事对万物一视同仁圣人不情感用事对百姓一视同仁执子之手与子偕老当男女主人公含情脉脉看着对方说了句执子之手与子偕老女方泪眼朦胧含羞地回一句讨厌啦这样的情节我们是不是见过很多但是我们来看看这句的原句死生契阔与子成说执子之手与子偕老于嗟阔兮不我活兮于嗟洵兮不我信兮意思是说战士之间的约定说要一起死现在和我约定的人都走了我怎么活啊赤裸裸的兄弟江湖战友友谊啊形容好基友的基情比男女之间的爱情要合适很多吧';
//str_split()切割字符串为一个数组,一个中文在utf_8为3个字符
$strdb = str_split($str,3);
//>11
$captcha_code = '';
//8>生成随机的汉子
for($i=0;$i<4;$i++){
//设置字体颜色，随机颜色
$fontcolor = imagecolorallocate($image, rand(0,120),rand(0,120), rand(0,120)); //0-120深颜色
//随机选取中文
$in = rand(0,count($strdb));
$cn = $strdb[$in];
//将中文记录到将保存到session的字符串中
$captcha_code .= $cn;
/*imagettftext (resource $image ,float $size ,float $angle ,int $x ,int $y,int $color,
string $fontfile ,string $text ) 幕布 ，尺寸，角度，坐标，颜色，字体路径，文本字符串
mt_rand()生成更好的随机数,比rand()快四倍*/
imagettftext($image, mt_rand(20,24),mt_rand(-60,60),(40*$i+20),mt_rand(30,35),$fontcolor,$fontface,$cn);
}
//11>存到session
$_SESSION['authcode'] = $captcha_code;
//9>增加干扰元素，设置点
for($i=0;$i<200;$i++){
//设置点的颜色，50-200颜色比数字浅，不干扰阅读
$pointcolor = imagecolorallocate($image,rand(50,200), rand(50,200), rand(50,200));
//imagesetpixel — 画一个单一像素
imagesetpixel($image, rand(1,199), rand(1,59), $pointcolor);
}
//10>增加干扰元素，设置线
for($i=0;$i<4;$i++){
//设置线的颜色
$linecolor = imagecolorallocate($image,rand(80,220), rand(80,220),rand(80,220));
//设置线，两点一线
imageline($image,rand(1,199), rand(1,59),rand(1,199), rand(1,59),$linecolor);
}
//2>设置头部，image/png
header('Content-Type: image/png');
//3>imagepng() 建立png图形函数
imagepng($image);
//4>imagedestroy() 结束图形函数 销毁$image
imagedestroy($image);
The rendering is as follows
The above is the entire content of this article to help you implement PHP numerical verification code, PHP letter verification code, and PHP Chinese character verification code. I hope it will be helpful to your learning.
Articles you may be interested in:
- php image verification code code
- php5 image verification code implementation code
- PHP verification code code (latest modification , completely customized! )
- A beautiful php verification code class (share)
- The solution to the PHP verification code not showing only a small red cross
- ThinkPHP verification code Use a concise tutorial
- PHP to generate image verification code, click to switch examples
- PHP uses CURL to implement simulated login to a website with verification code
- Perfect solution to thinkphp verification Methods for code errors that cannot be displayed
- php sends SMS verification code to complete the registration function
Hot AI Tools
Undress AI Tool
Undress images for free
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undresser.AI Undress
AI-powered app for creating realistic nude photos
ArtGPT
AI image generator for creative art from text prompts.
Stock Market GPT
AI powered investment research for smarter decisions
Hot Article
Popular tool
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
20518
7
13631
4
![How to install Redis cluster on Linux_Linux distributed cache deployment solution [Advanced]](https://img.php.cn/upload/article/202602/08/2026020819395340210.jpg)
How to install Redis cluster on Linux_Linux distributed cache deployment solution [Advanced]
Feb 08, 2026 pm 07:39 PM
The Redis6 cluster must be created with redis-cli--cluster. It requires a minimum of 3 masters and 3 slaves, a total of 6 nodes. The client port and the corresponding cluster bus port (10000) must be opened. Correct configuration but blocked ports is a common cause of failure.
How to dynamically set arbitrary depth value of nested array in PHP
Mar 04, 2026 am 11:15 AM
This article introduces a safe and efficient method to use key path arrays (such as ['key1', 'key2', 'key3']) to assign values to the last nodes of multi-dimensional associative arrays, solve the problem of reference failure caused by value transfer, and take into account key existence verification.
How to import SQL files in mysql_mysql SQL file import method
Feb 09, 2026 pm 05:24 PM
The most common and reliable way to import SQL files into MySQL is the command line tool mysql, which supports cross-platform, high efficiency and stability, and is suitable for files of all sizes. It can also be executed in the client through the source command, or using graphical tools such as phpMyAdmin and MySQL Workbench.
PHP batch processing of color mode and resolution of pictures in PPT
Mar 02, 2026 am 10:18 AM
To read PPTX images with PHP, you need to decompress the ZIP package first, because the images are stored in the ppt/media/ directory; directly calling the image function will report an error; you must use ZipArchive to decompress, Imagick to process CMYK to RGB conversion and scaling, and update the rels and [Content_Types].xml files simultaneously.
![Where can I see the PHP operator priority table_php official operator priority [Reference]](https://img.php.cn/upload/article/202603/02/2026030211450568785.jpg)
Where can I see the PHP operator priority table_php official operator priority [Reference]
Mar 02, 2026 am 11:45 AM
The official description of PHP operator precedence is located at https://www.php.net/manual/en/language.operators.precedence.php. You need to directly search for "operatorprecedence" or manually enter the URL to access; == and === have the same priority and belong to the same level; error-prone combinations include &&/|| and and/or, ?: and ??, new and []; complex expressions must be bracketed.
Number statistics in pyramid loop in PHP: correct counting method of total, odd and even numbers
Mar 04, 2026 pm 01:30 PM
This article explains in detail how to accurately count the total number, odd number and even number of all generated numbers in the PHP pyramid printing loop, correct common logic errors (such as misuse of variables, confusion of counting objects), and provide runnable examples and key precautions.
How to deal with character sets after mysql upgrade_mysql encoding migration instructions
Feb 09, 2026 pm 07:17 PM
After the MySQL 8.0 upgrade, the default character set becomes utf8mb4, but the old table character set remains unchanged; latin1/utf8 tables need to be manually migrated, and the source character set must be specified when exporting. ALTERTABLECONVERT will re-encode the data, and the connection layer must explicitly declare utf8mb4.
How to install ThinkPHP with composer_Steps to deploy TP framework using composer
Feb 12, 2026 am 06:27 AM
The ThinkPHP stable version should be clearly specified, such as using composercreate-projecttopthink/thinktp6^6.3 to install the TP6.3LTS version to avoid pulling non-production-ready beta versions because dev-master has switched to the TP8 preview version.
