search
HomeBackend DevelopmentPHP Tutorial辛星和您用更简单的方式去实现PHP中的验证码

       说实话,提到验证码我想大家都不会陌生,确实,验证码还是挺常见的,现在搜索一下PHP的验证码类简直是海量的数据,那我们今天就来实现一个自己的验证码把,不过它比较简单,这也是我说的用更简单的方式去实现一个验证码。

       总的来说分成两步,第一步就是先实现一个验证码,第二步就是通过这个验证码来进行验证,我们先看一下如何去实现这个验证码,当然这里需要用到gd库的知识,请看下面的代码示例:

<?php //首先要开启sessionsession_start();//说明这是一张图片header("Content-type:image/png");//用来动态生成的数字和字母组合$str = "3,4,5,6,7,8,9,a,b,c,d,e,f,g";//转化为数组$list = explode(",",$str);//得到该数组的下标的最大值$max = count($list) - 1;//用于表示该验证码$verify = "";//生成验证码字符串for($i = 0; $i <5;$i ++){	$rand = mt_rand(0,$max);	$verify .= $list[$rand];}//写入session$_SESSION['code'] = $verify;//生成一个58x28的图片$im = imagecreate(58,28);//产生黑色$black = imagecolorallocate($im,0,0,0);//产生白色$white = imagecolorallocate($im,255,255,255);//先用白色背景把图片刷成白色imagefill($im,0,0,$white);//然后把字符串写到图片上去imagestring($im,5,10,8,$verify,$black);//生成png图片,并且显示到屏幕上imagepng($im);//销毁该图片imagedestroy($im);

      这里顺便说一下画图的基本步骤把:首先创建一个图像,我们用imagecreate函数,然后用imagecolorallocate来调色,然后用各种imagexxx来绘制图像,最后用imagexxx来生成各种样式的图片,最后imagedestroy来销毁图片,大致都是这么一个流程。其中我感觉比较值得一提的是imagestring的参数,第一个表示绘画的图片这个没的说,第二额参数表示的是字体,如果为0,1,2,3,4,5则表示内置字体,第三个参数表示绘画的左上角的x坐标,第四个表示绘画的左上角的y坐标,第五个参数是颜色,我们这里采用了黑色来绘图。

来看一下我们生成的图片是什么样子的把:


那么我们怎么使用该验证码呢?既然文件都写好了,那么我们再写一个文件来导入该验证码就可以了,然后从session里面来得到它的值,看如下代码:

	
辛星和您用更简单的方式去实现PHP中的验证码

   这里使用了部分Javascript,如果读者不熟悉Javascript,那么大可以跳过去,下面是运行效果截图:


看,当然,真正的工程要复杂的多,这里给出的是一个示例程序,希望我们一同进步。。



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
How to make PHP applications fasterHow to make PHP applications fasterMay 12, 2025 am 12:12 AM

TomakePHPapplicationsfaster,followthesesteps:1)UseOpcodeCachinglikeOPcachetostoreprecompiledscriptbytecode.2)MinimizeDatabaseQueriesbyusingquerycachingandefficientindexing.3)LeveragePHP7 Featuresforbettercodeefficiency.4)ImplementCachingStrategiessuc

PHP Performance Optimization Checklist: Improve Speed NowPHP Performance Optimization Checklist: Improve Speed NowMay 12, 2025 am 12:07 AM

ToimprovePHPapplicationspeed,followthesesteps:1)EnableopcodecachingwithAPCutoreducescriptexecutiontime.2)ImplementdatabasequerycachingusingPDOtominimizedatabasehits.3)UseHTTP/2tomultiplexrequestsandreduceconnectionoverhead.4)Limitsessionusagebyclosin

PHP Dependency Injection: Improve Code TestabilityPHP Dependency Injection: Improve Code TestabilityMay 12, 2025 am 12:03 AM

Dependency injection (DI) significantly improves the testability of PHP code by explicitly transitive dependencies. 1) DI decoupling classes and specific implementations make testing and maintenance more flexible. 2) Among the three types, the constructor injects explicit expression dependencies to keep the state consistent. 3) Use DI containers to manage complex dependencies to improve code quality and development efficiency.

PHP Performance Optimization: Database Query OptimizationPHP Performance Optimization: Database Query OptimizationMay 12, 2025 am 12:02 AM

DatabasequeryoptimizationinPHPinvolvesseveralstrategiestoenhanceperformance.1)Selectonlynecessarycolumnstoreducedatatransfer.2)Useindexingtospeedupdataretrieval.3)Implementquerycachingtostoreresultsoffrequentqueries.4)Utilizepreparedstatementsforeffi

Simple Guide: Sending Email with PHP ScriptSimple Guide: Sending Email with PHP ScriptMay 12, 2025 am 12:02 AM

PHPisusedforsendingemailsduetoitsbuilt-inmail()functionandsupportivelibrarieslikePHPMailerandSwiftMailer.1)Usethemail()functionforbasicemails,butithaslimitations.2)EmployPHPMailerforadvancedfeatureslikeHTMLemailsandattachments.3)Improvedeliverability

PHP Performance: Identifying and Fixing BottlenecksPHP Performance: Identifying and Fixing BottlenecksMay 11, 2025 am 12:13 AM

PHP performance bottlenecks can be solved through the following steps: 1) Use Xdebug or Blackfire for performance analysis to find out the problem; 2) Optimize database queries and use caches, such as APCu; 3) Use efficient functions such as array_filter to optimize array operations; 4) Configure OPcache for bytecode cache; 5) Optimize the front-end, such as reducing HTTP requests and optimizing pictures; 6) Continuously monitor and optimize performance. Through these methods, the performance of PHP applications can be significantly improved.

Dependency Injection for PHP: a quick summaryDependency Injection for PHP: a quick summaryMay 11, 2025 am 12:09 AM

DependencyInjection(DI)inPHPisadesignpatternthatmanagesandreducesclassdependencies,enhancingcodemodularity,testability,andmaintainability.Itallowspassingdependencieslikedatabaseconnectionstoclassesasparameters,facilitatingeasiertestingandscalability.

Increase PHP Performance: Caching Strategies & TechniquesIncrease PHP Performance: Caching Strategies & TechniquesMay 11, 2025 am 12:08 AM

CachingimprovesPHPperformancebystoringresultsofcomputationsorqueriesforquickretrieval,reducingserverloadandenhancingresponsetimes.Effectivestrategiesinclude:1)Opcodecaching,whichstorescompiledPHPscriptsinmemorytoskipcompilation;2)DatacachingusingMemc

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.