php实现点击可刷新验证码

验证码类文件 CreateImg.class.php

<?php 

class ValidationCode
{
private $width,$height,$codenum;
public $checkcode;   //产生的验证码
private $checkimage;  //验证码图片
private $disturbColor = ''; //干扰像素 

function __construct($width='80',$height='20',$codenum='4')
{
  $this->width=$width;
  $this->height=$height;
  $this->codenum=$codenum;
}
function outImg()
{
  //输出头
  $this->outFileHeader();
  //产生验证码
  $this->createCode(); 

  //产生图片
  $this->createImage();
  //设置干扰像素
  $this->setDisturbColor();
  //往图片上写验证码
  $this->writeCheckCodeToImage();
  imagepng($this->checkimage);
  imagedestroy($this->checkimage);
} 

private function outFileHeader()
{
  header ("Content-type: image/png");
} 

private function createCode()
{
  $this->checkcode = strtoupper(substr(md5(rand()),0,$this->codenum));
} 

private function createImage()
{
  $this->checkimage = @imagecreate($this->width,$this->height);
  $back = imagecolorallocate($this->checkimage,255,255,255);
  $border = imagecolorallocate($this->checkimage,0,0,0);
  imagefilledrectangle($this->checkimage,0,0,$this->width - 1,$this->height - 1,$back); // 白色底
  imagerectangle($this->checkimage,0,0,$this->width - 1,$this->height - 1,$border);  // 黑色边框
} 

private function setDisturbColor()
{
  for ($i=0;$i<=200;$i++)
  {
  $this->disturbColor = imagecolorallocate($this->checkimage, rand(0,255), rand(0,255), rand(0,255));
  imagesetpixel($this->checkimage,rand(2,128),rand(2,38),$this->disturbColor);
  }
} 

private function writeCheckCodeToImage()
{
  for ($i=0;$i<=$this->codenum;$i++)
  {
  $bg_color = imagecolorallocate ($this->checkimage, rand(0,255), rand(0,128), rand(0,255));
  $x = floor($this->width/$this->codenum)*$i;
  $y = rand(0,$this->height-15);
  imagechar ($this->checkimage, rand(5,8), $x, $y, $this->checkcode[$i], $bg_color);
  }
}
function __destruct()
{
  unset($this->width,$this->height,$this->codenum);
}
}
?> 

包含文件 imgcode.php

<?php
session_start();
require_once('CreateImg.class.php');
$image = new ValidationCode('80','20','4');  //图片长度、宽度、字符个数
$image->outImg();
$_SESSION['validationcode'] = $image->checkcode; //存贮验证码到 $_SESSION 中
?>

前台文件 demo.php

?php
session_start();
$test = $_POST['test'];
$test = strtoupper(trim($test));
$submit = $_POST['submit'];
if(isset($submit)){
if($test==$_SESSION['validationcode']){
  echo 'true';
} else {
  echo 'false';
}
}
?> 

<html>
<head>
<title>Image</title>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<script language="javascript">
function newgdcode(obj,url) {
obj.src = url+ '?nowtime=' + new Date().getTime();
//后面传递一个随机参数，否则在IE7和火狐下，不刷新图片
}
</script>
<body>
<img src="imgcode.php" alt="看不清楚，换一张" align="absmiddle" style="cursor: pointer;" onclick="javascript:newgdcode(this,this.src);" />
<form method="POST" name="form1" action="image.php">
<input type="text" name="test">
<br />
<input type="submit" name="submit" value="提交">
</form>
</body>
</head>
</html> 

以上就是为大家介绍的php点击验证码即可刷新的全部代码，希望对大家的学习有所帮助。