本文实例为大家分享了php点击可刷新验证码的具体代码，供大家参考，具体内容如下

验证码类文件 CreateImg.class.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

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';

}

}

?>

Image

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

}

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。