Backend DevelopmentPHP TutorialDetailed explanation of the website verification code function code using PHPDetailed explanation of the website verification code function code using PHP
This article mainly introduces the method of using php to implement the website verification code function. It has a very good reference value. Let’s take a look at it with the editor.
Verification code is a security measure commonly used on websites, and it is also a skill that is difficult for new webmasters to master. Here I will introduce it to you. A simple and effective verification code implementation method.
Before starting
Before we officially start, we need to turn on php's gd2 graphics library support (search for "php_gd2.dll" in php.ini, and find "; extension=php_gd2.dll" and remove the semicolon at the beginning of the sentence).
You can refer to: How to open the gd2 library of php
Core: img.php
This page generates a verification code and writes the correct value Enter Session
Randomly enter a 4-digit verification code
##$check=rand(1000,9999);
Write the generated verification code into the session
Session_start(); $_SESSION["check"] = $check;
Create A picture
$im = imagecreate(80,30);
imagefill($im,0,0,ImageColorAllocate($im, 255,255,255));
##Use imageline to randomly draw two solid lines
$y1=rand(0,30); $y2=rand(0,30); $y3=rand(0,30); $y4=rand(0,30); imageline($im,0,$y1,70, $y3,000); imageline($im,0,$y2,70, $y4,000);
Draw text in random positions
$strx=rand(3,15); $stry=rand(2,15); imagestring($img,5,$strx,$stry,substr($check,0,1),ImageColorAllocate($img,34,87,100)); $strx+=rand(15,20); $stry=rand(2,15); imagestring($img,5,$strx,$stry,substr($check,1,1),ImageColorAllocate($img,781,117,78)); $strx+=rand(15,20); $stry=rand(2,15); imagestring($img,5,$strx,$stry,substr($check,2,1),ImageColorAllocate($img,160,40,40)); $strx+=rand(15,20); $stry=rand(2,15); imagestring($img,5,$strx,$stry,substr($check,3,1),ImageColorAllocate($img,25,55,10));
Output image
Header("Content-type: image/PNG");
ImagePNG($img);
End, the following is the complete code
User interface: index.phpI believe everyone knows how to do it, so I will give the code directly
<!DOCTYPE html> <html> <body> <form action="action.php" method="post"> <input type="text" name="cikle" placeholder="验证码"> <br> <img src="/static/imghwm/default1.png" data-src="img.php" class="lazy" id="cikle" style="max-width:90%" alt="Detailed explanation of the website verification code function code using PHP" ><input type="submit" value="Submit"> </form> </body> </html>The above code passes the value entered by the user to "action.php"
Check: action.phpThis step is to compare the user input value with the value in the session.
If they are equal, the output will be "correct"
If they are not equal, the output will be "incorrect"
<?php Session_start(); if ($_SERVER["REQUEST_METHOD"] == "POST") { if($_SESSION["check"]!=intval($_POST["cikle"])){ echo "不正确"; }else{ echo "正确"; } }
The above is the detailed explanation of the website verification code function code using PHP. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!
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