效果：
myvcode.class.php：封装创建验证码的类
/*<br>* file:myvcode.class.php<br>* 验证码类,类名Vcode<br>*/<br>class Vcode<br>{<br>private $width; /*验证码宽度*/<br>private $height; /*验证码高度*/<br>private $codeNum; /*验证码字符个数*/<br>private $checkCode; /*验证码字符*/<br>private $image; /*验证码资源*/<br>private $pixNum; /*绘制干扰点的个数*/<br>private $lineNum; /*绘制干扰线的条数*/
/*<br>*构造方法实例化验证码对象，并初始化数据<br>*@param int $width 设置默认宽度<br>*@param int $height 设置默认高度<br>*@param int $codeNum 设置验证码中的字符个数<br>*@param int $pixNum 设置干扰点的个数<br>*@param int $lineNum 设置干扰线的数量<br>*/<br>function __construct($width=80,$height=40,$codeNum=4,$pixNum=40,$lineNum=5)<br>{<br>$this->width = $width;<br>$this->height = $height;<br>$this->codeNum = $codeNum;<br>$this->pixNum = $pixNum;<br>$this->lineNum = $lineNum;<br>}<br>/*内部私有方法,创建图像资源*/<br>private function getCreateImage()<br>{<br>$this->image = imagecreatetruecolor($this->width, $this->height);<br>$white = imagecolorallocate($this->image,0xff,0xff,0xff);<br>imagefill($this->image, 0, 0, $white);<br>$black = imagecolorallocate($this->image,0,0,0);<br>imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $black);<br>}<br>/*内部私有方法,绘制字符，去掉o0Llz和012*/<br>private function createCheckCode()<br>{<br>$code = '3456789abcdefghijkmnpqrstuvwxyABCDEFGHIJKMNPQRSTUVWXY';<br>$this->checkCode = "";<br>for($i=0; $icodeNum;$i++)<br>{<br>$char = $code{rand(0,strlen($code) - 1)};<br>$this->checkCode .= $char;<br>$fontColor = imagecolorallocate($this->image, rand(0,128), rand(0,128),rand(0,128));<br>$fontSize = rand(3,5);<br>$x = rand(0,$this->width-imagefontwidth($fontSize));<br>$y = rand(0,$this->height-imagefontheight($fontSize));<br>imagechar($this->image, $fontSize, $x, $y, $char, $fontColor);<br>}<br>}<br>/*内部私有方法设置干扰元素*/<br>private function setDisturbColor()<br>{<br>/*绘制干扰点*/<br>for($i=0; $ipixNum; $i++)<br>{<br>$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));<br>imagesetpixel($this->image, rand(1,$this->width-2), rand(1,$this->height-2), $color);<br>}<br>/*绘制干扰线*/<br>for($i=0; $ilineNum; $i++)<br>{<br>$color = imagecolorallocate($this->image, rand(0,255), rand(0,255), rand(0,255));<br>imageline($this->image, rand(1,$this->width / 2), rand(1,$this->height / 2),<br>rand($this->width / 2,$this->width – 2), rand($this->height / 2,$this->height – 2), $color);
}<br>}<br>/*开启session保存 利用echo 输出图像*/<br>function __toString()<br>{<br>$_SESSION['code'] = strtoupper($this->checkCode);<br>$this->getCreateImage();<br>$this->createCheckCode();<br>$this->setDisturbColor();<br>$this->outputImg();<br>}<br>/*内部私有方法输出图像*/<br>private function outputImg()<br>{<br>header("content-type:image/png");<br>imagepng($this->image);<br>}<br>/*析构方法，释放对象*/<br>function __destruct()<br>{<br>imagedestroy($this->image);<br>}<br>}<br>?>imgcode.php输出图像
<?php
session_start();
require_once('myvcode.class.php');
echo new Vcode();
?>
test.html:同过img标签引用
<img src="imgcode.php" alt="PHP制作图形验证码代码分享，php图形验证码代码_PHP教程" >
可以加一个a标签，用js实现换一张效果：
/*局部刷新换验证码*/
function changeCode()
{
var imgcode = document.getElementById(‘code');
var change = document.getElementById(‘change');
change.onclick = function()
{
/*必须加后面的参数才能刷新*/
imgcode.src='code.php?tm'+Math.random();
}
}
code和change分别是img和a的id
这个是phpcms的验证码，经过十几万个网站经验的，非常好用
session_start();
$enablegd = 1;
//判断图像处理函数是否存在
$funcs = array('imagecreatetruecolor','imagecolorallocate','imagefill','imagestring','imageline','imagerotate','imagedestroy','imagecolorallocatealpha','imageellipse','imagepng');
foreach($funcs as $func)
{
if(!function_exists($func))
{
$enablegd = 0;
break;
}
}
ob_clean(); //清理缓冲
if($enablegd)
{
//create captcha
$consts = 'cdfgkmnpqrstwxyz23456';
$vowels = 'aek23456789';
for ($x = 0; $x {
$const[$x] = substr($consts, mt_rand(0,strlen($consts)-1),1); //获取$consts中的一个随机数
$vow[$x] = substr($vowels, mt_rand(0,strlen($vowels)-1),1); //获取$vowels中的一个随机数
}
$radomstring = $const[0] . $vow[0] .$const[2] . $const[1] . $vow[1] . $const[3] . $vow[3] . $const[4];
$_SESSION['checkcode'] = $string = substr($radomstring,0,4); //显示4个字符
$imageX = strlen($radomstring)*8; //图像的宽
$imageY = 20; //图像的高
$im = imagecreatetruecolor($imageX,$imageY); //新建一个真彩色图像
//creates two variables to store color
$background = imagecolorallocate($im, rand(180, 250), rand(180, 250), rand(180, 250)); //背景色
$foregroundArr = array(imagecolorallocate($im, rand(0, 20), rand(0, 20), rand(0, 20)),
imagecolorallocate($im, rand(0, 20), rand(0, 10), rand(245, 255)),
imagecolorallocate($im, rand(245, ......余下全文>>
action.php
session_start();
$password = md5(trim($_POST['password']));
$str_reg=$_POST['number']; //用户填写的验证码
$str_reg = strtoupper($str_reg); //转换大写
if ($str_reg !=$_SESSION['yzm'] or empty($str_reg) )
{echo "验证码错误";
}
else
{
$_SESSION['yzm']=""; //清除session
……
执行数据库查询操作，验证用户名，密码
}
?>
