PHP realizes that clicking on the verification code or not seeing it clearly will refresh the verification code

This article mainly introduces the relevant information on how to use the GD library to create verification codes in PHP (clicking on the verification code or not seeing it clearly will refresh the verification code). Friends who need it can refer to it. I hope it can help everyone.

This is a page that uses the GD library to generate a verification code

test.PHP

<?php 
header(&#39;Content-Type:image/jpeg&#39;); 
 $img = imagecreatetruecolor(100, 40); 
 $black = imagecolorallocate($img, 0x00, 0x00, 0x00); 
 $green = imagecolorallocate($img, 0x00, 0xFF, 0x00); 
 $white = imagecolorallocate($img, 0xFF, 0xFF, 0xFF); 
 imagefill($img,0,0,$white); //生成随机的验证码 
 $code = &#39;&#39;; 
 for($i = 0; $i < 4; $i++) { $code .= rand(0, 9); } 
 imagestring($img, 5, 10, 10, $code, $black); 
 //加入噪点干扰 
 for($i=0;$i<50;$i++) { 
  imagesetpixel($img, rand(0, 100) , rand(0, 100) , $black); 
  imagesetpixel($img, rand(0, 100) , rand(0, 100) , $green); 
 } //输出验证码 header("content-type: image/png"); 
 imagepng($img); 
 imagedestroy($img); 
?>

This is a page that can be partially refreshed and verified after clicking on the verification code or seeing it clearly. Code

test2.php

<script type="text/javascript"> 
 function shuaxin() 
 { 
  document.getElementById(&#39;code&#39;).src = "test.php?"+Math.random(); 
 } 
</script> 
<input type="text"><br /> 
<img id="code" src="test.php" onclick="shuaxin()" /> 
<span onclick="shuaxin()">看不清？</span><br />

is shown below:

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