PHP programming must learn verification code every day

PHP programming must learn verification code every day_php skills

WBOY

Release： 2016-05-16 19:57:49

Original

1670 people have browsed it

This article shares the implementation code of PHP image verification code for everyone for your reference. The specific content is as follows

1. Verification code image generation
captcha.php

//1.生成100*30大小的图片,默认为黑色
$image = imagecreatetruecolor(100,30);
//创建白色底图
$bgcolor = imagecolorallocate($image,255,255,255);
//用白色填充黑色
imagefill ($image,0,0,$bgcolor);

//2.随机显示数字或字母
$captch_code = "";
for($i=0;$i<4;$i++){
 $fontsize=6;
 $fontcolor=imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));
 $data = "abcdefghijkmnpqrstuvwxy3456789";
 $fontcontent =substr($data,rand(0,strlen($data)),1);
 $captch_code .=$fontcontent;
 $x = ($i*100/4)+rand(5,10);
 $y = rand(5,10);

 imagestring($image, $fontsize, $x, $y, $fontcontent,$fontcolor);
}
$_SESSION["authcode"] = $captch_code;

//3.增加干扰
//干扰点
for($i=0;$i<100;$i++){
 $pointcolor=imagecolorallocate($image,rand(50,200),rand(50,200),rand(50,200));
 imagesetpixel($image,rand(1,99),rand(1,29),$pointcolor);
}

//干扰线
for($i=0;$i<2;$i++){
 $linecolor=imagecolorallocate($image,rand(80,220),rand(80,220),rand(80,220));
 imageline($image,rand(1,99),rand(1,29),rand(1,99),rand(1,29),$linecolor);
}


header("content-type:image/png");
imagepng($image);

Copy after login

2. The page implements the verification code function
form.php

<&#63;php
if(isset($_POST["authcode"])){
 session_start();
 if(strtolower($_POST["authcode"])==$_SESSION["authcode"]){
  echo "OK";
 }else{
  echo "NO";
 }
}

&#63;>


<!doctype html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>Document</title>
</head>
<body>
<form action="form.php" method="post">
 <p>验证码图片: <img id="img" border="1" src="captcha.php&#63;r=<&#63;php echo rand()&#63;>" alt="">
 <a href="javascript:void(0)" onclick="document.getElementById('img').src='captcha.php&#63;r'+Math.random() ">换一个</a>
 </p>
 <p><input type="text" name="authcode"></p>
 <p><input type="submit" value="提交"></p>

</form>
</body>
</html>

Copy after login

The above is the entire content of this article to help you easily implement PHP image verification code.