PHP implements login verification code verification function php example-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

PHP implements login verification code verification function php example

jacklove

Jun 23, 2018 pm 04:14 PM

phpLogin verification code

This article mainly introduces the verification code verification function in PHP in detail. It is mainly implemented by using the SESSION function in PHP. It has certain reference value. Interested friends can refer to it

The verification code is verified by using the SESSION function in PHP.

Declare the function at the top session_start(); Tell the server that we want to use this function.

session_start();

The next thing we use is the code to implement the verification code. Here we use English numeric codes as an example.

$image = imagecreatetruecolor(100, 30); //创建一个100×30的画布
$white = imagecolorallocate($image,255,255,255);//白色
imagefill($image,0,0,$white);//覆盖黑色画布

Then declare an empty variable before the verification code is implemented to store the verification code.

$session = ""; //空变量 ，存放验证码
for($i=0;$i<4;$i++){
 $size = 6;
 $x = $i*25+mt_rand(5,10);
 $y = mt_rand(5,10);
 $sizi_color = imagecolorallocate($image,mt_rand(80,220),mt_rand(80,220),mt_rand(80,220));
 $char = join("",array_merge(range(&#39;a&#39;,&#39;z&#39;),range(&#39;A&#39;,&#39;Z&#39;),range(0,9)));
 $char = str_shuffle($char);
 $char = substr($char,0,1);
 imagestring($image,$size,$x,$y,$char,$sizi_color);
 $session .= $char ; //把验证码的每一个值赋值给变量
}
 $_SESSION[&#39;session&#39;] = $session; //这个变量的值与用户输入的值相等

for($k=0;$k<200;$k++){
 $rand_color = imagecolorallocate($image,mt_rand(50,200),mt_rand(50,200),mt_rand(50,200));
 imagesetpixel($image,mt_rand(1,99),mt_rand(1,29),$rand_color);
}
for($n=0;$n<5;$n++){
 $line_color = imagecolorallocate($image,mt_rand(80,220),mt_rand(80,220),mt_rand(80,220));
 imageline($image,mt_rand(1,99),mt_rand(1,29),mt_rand(1,99),mt_rand(1,29),$line_color);
}
header(&#39;content-type:image/png&#39;);//设置文件输出格式
imagepng( $image ); //以png格式输出$image图像
imagedestroy( $image ); //销毁图像

Use POST method to receive verification code. The strtolower function makes the server case-insensitive. This can effectively reduce the user's input error rate.

if(isset($_POST[&#39;session&#39;])){
 session_start();
 if(strtolower($_POST[&#39;session&#39;])==strtolower($_SESSION[&#39;session&#39;])){
  echo&#39;<font color="#0000CC">输入正确</form>&#39;;
 }else{
  echo &#39;<font color="#CC0000"><b>输入错误</b></font>&#39;;
 }
 exit();
}

The following is the HTML page code.

<!DOCTYPE html>
<html>
<head>
 <meta charset="utf-8"/>
 <title>确认验证码</title>
</head>
<body>
 <form method="post" action="./tushu.php">
 <p>验证码图片:<img  src="/static/imghwm/default1.png"  data-src="http://localhost//xxx.php"  class="lazy"  id="img" border="1"     style="max-width:90%"  style="max-width:90%" alt="PHP implements login verification code verification function php example" ></p>
 <a href="javascript:void(0)" rel="external nofollow"  onclick="document.getElementById(&#39;img&#39;).src=&#39;http://localhost//xxx.php&#39;">看不清？换一个</a>
 <p>请输入图片中的验证码：<input type="text" name="session" value=""/></p>
 <p><input type="submit" value="提交" style="padding:6px 10px;"></p>
 </form>
</body>
</html>

Summary

The above is the PHP implementation introduced by the editor Login verification code verification function, I hope it will be helpful to everyone. If you have any questions, please leave me a message and the editor will reply to you in time. I would also like to thank you all for your support of the php Chinese website!

Articles you may be interested in:

How to use Composer to install ThinkPHP5 in a windows environment

PHP generates the relevant content of the request signature required by Tencent Cloud COS interface

PHP access database configuration general method (json) Qiao

The above is the detailed content of PHP implements login verification code verification function php example. For more information, please follow other related articles on the PHP Chinese website!

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

The Continued Use of PHP: Reasons for Its EnduranceApr 19, 2025 am 12:23 AM

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python: Exploring Their Similarities and DifferencesApr 19, 2025 am 12:21 AM

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

See all articles