Tutorial on writing a pure digital verification code in PHP

零下一度
Release: 2023-03-11 07:28:01
Original
2822 people have browsed it

Now let’s talk about the simple pure digital 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  //11>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[&#39;authcode&#39;] = $captcha_code;  //8>增加干扰元素,设置雪花点  for($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(&#39;Content-Type: image/png&#39;);  //3>imagepng() 建立png图形函数  imagepng($image);  //4>imagedestroy() 结束图形函数 销毁$image  imagedestroy($image);
 
接着就是静态页的代码了:index.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional
//EN" "、www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns=" 
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>无标题文档</title>
</head><body><form method="post" action="./form.php">  
<p>验证码: <img id="captcha_img" border=&#39;1&#39; src=&#39;./captcha.php?r=echo rand(); ?>&#39; style="width:100px; height:30px" />    
<a href="javascript:void(0)" onclick="document.getElementById(&#39;captcha_img&#39;).src=&#39;./captcha.php?r=&#39;+Math.random()">换一个?</a>  </p>  <P>请输入验证码:<input type="text" name=&#39;authcode&#39; value=&#39;&#39;/></p>  <p><input type=&#39;submit&#39; value=&#39;提交&#39; style=&#39;padding:6px 5px;&#39;/></p></form></body></html>
从index.html可以看到,提交的表单是到form.php的,所以还要有一个判断的form.php代码:
<?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($_REQUEST[&#39;authcode&#39;])){    
session_start();    //strtolower()小写函数    if(strtolower($_REQUEST[&#39;authcode&#39;])== $_SESSION[&#39;authcode&#39;]){      
//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(&#39;输入错误!&#39;);";      echo "document.location=\"./form.php\"";      echo "</script>";    }    
exit(); 
 }
Copy after login


The above is the detailed content of Tutorial on writing a pure digital verification code in PHP. For more information, please follow other related articles on the PHP Chinese website!

Related labels:
source:php.cn
Statement of this Website
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
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template