PHP programming must learn verification code every day, PHP programming verification code

PHP programming must learn verification code every day, PHP programming verification code_PHP tutorial

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Release： 2016-07-12 08:57:49

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PHP programming must learn verification code every day, PHP programming verification code

This article shares the implementation code of PHP picture verification code for everyone, and shares it with you for your reference. The specific content 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);

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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>

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

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