php验证码无错版（无刷新更换验证码）

为了这个验证码，在网上找了N多的资料，发现那些网上的代码不是这错误就是那错误，

还有些文章方法写得很粗，对一个新手来说，简直不知从何处下手，

我真搞不懂他们为什么要贴出来，真是误人子弟！

下面我将修改后（测试通过）的代码和方法写出来供大家参考：

 

第一步，新建一个code.php的文件，在code.php加入下面这些代码并保存

<?php
/**
*  Verification Code Class
*
*  Used to anti-spam base at PHP GD Lib
*  @author Eric,<[e-mail]>
*  @version 1.0
*  @copyright  Ereesoft Inc. 2009
*  @update 2009-05-14 22:32:05
*  @example
*      session_sratr();
*      $vcode = new Vcode();
*      $vcode->setLength(5);
*      $_SESSION['vcode'] = $vcode->paint();// To be encrypted by MD5
*/
class Vcode{
    /**
     *  @var $width The width of the image,auto Calculated 验证图片宽度，程序自动计算
     */
    private $width;
    /**
     *  @var $height Image height 验证图片高度
     */
    private $height;
    /**
     *  @var $length Verification Code lenght 验证码长度
     */
    private $length;
    /**
     *  @var $bgColor Image background color default random 验证图片背景色
     */
    private $bgColor;
    /**
     *  @var $fontColor The text color 验证码颜色
     */
    private $fontColor;
    /**
     *  @var $dotNoise The number of noise 噪点数量
     */
    private $dotNoise;
    /**
     *  @var $lineNoise The number of noise lines 干扰线数量
     */
    private $lineNoise;
    /**
     *  @var $im image resource GD图像操作资源
     */
    private $im;
   
    /**
     *  void Vcode::Vcode()
     *
     *  The constructor
     */
    public function Vcode(){
        $this->dotNoise = 5;//初始化噪点数量
        $this->lineNoise = 0;//初始化干扰线数量
    }
     /**
     *  void Vcode::setLength(integer $length)
     *
     *  Set Verification Code length
     *  @access public
     *  @param integer $length;
     *  @return void
     */
    public function setLength($length){
        $this->length = $length;
    }
    /**
     *  void Vcode::setBgColor(string $bgColor)
     *
     *  Set background color of the Verification Image
     *  @access public
     *  @param string $bgColor e.g.: #ffffff;可以直接使用css书写中的16进制写法，但不可简写
     *  @return void
     */
    public function setBgColor($bgColor){
        $this->bgColor = sscanf($bgColor, '#%2x%2x%2x');
    }
    /**
     *  void Vcode::setFontColor(string $fontgColor)
     *
     *  Set text color of the Verification Image
     *  @access public
     *  @param string $fontColor e.g.: #ffffff;可以直接使用css书写中的16进制写法，但不可简写
     *  @return void
     */
    public function setFontColor($fontColor){
        $this->fontColor = sscanf($fontColor, '#%2x%2x%2x');
    }
    /**
     *  void Vcode::setDotNoise(integer $num)
     *
     *  How many noise dots want to draw
     *  @access public
     *  @param integer $num Too much will lower performance
     *  @return void
     */
    public function setDotNoise($num){
        $this->dotNoise = $num;//手动设置噪点数量后，会覆盖初始设置
    }
    /**
     *  void Vcode::setLineNoise(integer $num)
     *
     *  How many noise lines want to draw
     *  @access public
     *  @param integer $num Too much will lower performance
     *  @return void
     */
    public function setLineNoise($num){
        $this->lineNoise = $num;//手动设置干扰线数量后，会覆盖初始设置
    }
    /**
     *  String Vcode::randString()
     *
     *  Create Random characters 生成随机字符串
     *  @access private
     *  @return String
     */
    private function randString(){
        $string = strtoupper(md5(microtime().mt_rand(0,9)));
        return substr($string, 0, $this->length);
    }
    /**
     *  void Vcode::drawDot()
     *
     *  Draw dots noise 根据制定的数量随机画噪点，噪点颜色也随机
     *  @access private
     */
    private function drawDot(){
        for($i=0; $i<$this->dotNoise; $i++){
            $color = imagecolorallocate($this->im,
                                        mt_rand(0,255),
                                        mt_rand(0,255),
                                        mt_rand(0,255));//生成随机颜色
            imagesetpixel($this->im,
                            mt_rand(0,$this->width),
                            mt_rand(0,$this->height),
                            $color);//在随机生成的坐标上画噪点
        }
    }
    /**
     *  void Vcode::drawLine()
     *
     *  Draw line noise 随机颜色随机画干扰线
     *  @access private
     */
    private function drawLine(){
        for($i=0; $i<$this->lineNoise; $i++){
            $color = imagecolorallocate($this->im,
                                        mt_rand(0,255),
                                        mt_rand(0,255),
                                        mt_rand(0,255));//随机生成颜色
            imageline($this->im,
                        mt_rand(0,$this->width),
                        mt_rand(0,$this->height),
                        mt_rand(0,$this->width),
                        mt_rand(0,$this->height),
                        $color);//在随机生成的坐标上画干扰线
        }
    }
    /**
     *  String Vcode::paint()
     *
     *  Create image and output
     *  @access public
     *  @return string  The Verification Code to be encrypted by MD5
     */
    public function paint(){
   
        if(empty($this->length)) $this->length = 4;//验证码默认长度为4
       
        $this->width =  $this->length*12+4 ;//计算验证图片宽度
        $this->height = 20;//制定验证码图片高度
        $this->im = imagecreate($this->width, $this->height);//创建画布
       
        if(empty($this->bgColor) || empty($this->fontColor)){//如果没有设置前景色和背景色则全部随机
            //避免前景色和背景色过于接近，背景色（0-130）的随机范围与前景色（131-255）分开
            imagecolorallocate( $this->im,
                                mt_rand(0,130),
                                mt_rand(0,130),
                                mt_rand(0,130));
                               
            $randString = $this->randString();
           
            for($i=0; $i<$this->length; $i++){
                $fontColor = imagecolorallocate($this->im,
                                                mt_rand(131,255),
                                                mt_rand(131,255),
                                                mt_rand(131,255));
                imagestring($this->im, 3,
                            $i*10+8,
                            mt_rand(0,8),
                            $randString{$i},
                            $fontColor);
                            //单个验证码字符高度随机，避免被OCR
            }
           
        } else {//如果设置了背景色和前景色，则不使用随机颜色
       
            imagecolorallocate( $this->im,
                                $this->bgColor[0],
                                $this->bgColor[1],
                                $this->bgColor[2]);
            $randString = $this->randString();
            $fontColor = imagecolorallocate($this->im,
                                            $this->fontColor[0],
                                            $this->fontColor[1],
                                            $this->fontColor[2]);
            for($i=0;$i<$this->length;$i++){
                imagestring($this->im, 3,
                            $i*10+8,
                            mt_rand(0,8),
                            $randString{$i},
                            $fontColor);//每个验证码字符高度仍然随机
            }
           
        }
       
        $this->drawDot();//绘制噪点
        $this->drawLine();//绘制干扰线
        imagepng($this->im);
        imagedestroy($this->im);
        return md5($randString);//返回MD5加密后的验证码，可直接放入session
       
    }
}

session_start();
$vcode = new Vcode();
$vcode->setLength(5);
$_SESSION['vcode']=$vcode->paint();// To be encrypted by MD5
?>

 

 

 

第二步：在登陆页面login.php中调用验证码(注意：login.php和code.php 需放到同一个目录里面)

//login.php里面的代码如下：

<form id="form1" name="form1" method="post" action="test.php">

// test.php为提交后的验证页面
  <input name="yzm" type="text" class="STYLE1" id="yzm" />
  <img src="code.php?image" onclick="this.src='code.php?image'"/>
  <input name="Submit" type="submit" id="Submit" value="submit" />
</form>

 

 

最后一步：开始验证输入的验证码是否正确，如果不正确，则返回登录页面

//创建一个test.php的测试页面，里面的代码如下

<?php
session_start();
//在页首先要开启session,
//error_reporting(2047);
session_destroy();

if($_POST[Submit]){
  if(md5($_POST[yzm])==$_SESSION['vcode']){
    echo "";
  }else{
     echo '<script>alert("验证码不正确，请重新输入！"); window.location.href="login.php"; </script>';
  }
}
?>

 

 

到此结束，百分百有效，绝不会出现乱码！