验证码的类及使用

<?php

session_start();

ini_set('display_errors', 'Off');

class CCheckCodeFile

{

       //验证码位数 www.2cto.com

       var $mCheckCodeNum  = 4;

       //产生的验证码

       var $mCheckCode   = '';

       //验证码的图片

       var $mCheckImage  = '';

       //干扰像素

       var $mDisturbColor  = '';

       //验证码的图片宽度

       var $mCheckImageWidth = '80';

       //验证码的图片宽度

       var $mCheckImageHeight  = '20';

       //输出头

       function OutFileHeader()

       {

              header ("Content-type: image/png");

       }

       //产生验证码

       function CreateCheckCode()

       {

              //$this->mCheckCode = strtoupper(substr(md5(rand()),0,$this->mCheckCodeNum));

              $this->mCheckCode = strtoupper(substr(rand(0,9999999999),0,$this->mCheckCodeNum));

              session_cache_expire(60);

              session_start();

              $_SESSION["code_str"] = $this->mCheckCode;

              return $this->mCheckCode;

       }

       //产生验证码图片

       function CreateImage()

       {

              $this->mCheckImage = @imagecreate ($this->mCheckImageWidth,$this->mCheckImageHeight);

              imagecolorallocate ($this->mCheckImage, 255, 255, 255);

              return $this->mCheckImage;

       }

       //设置图片的干扰像素

       function SetDisturbColor()

       {

              for ($i=0;$i<=128;$i++)

              {

                     $this->mDisturbColor = imagecolorallocate ($this->mCheckImage, rand(0,255), rand(0,255), rand(0,255));

                     imagesetpixel($this->mCheckImage,rand(1,100),rand(1,100),$this->mDisturbColor);

              }

       }

       //设置验证码图片的大小宽高

       function SetCheckImageWH($width,$height)

       {

              if($width==''||$height=='')return false;

              $this->mCheckImageWidth  = $width;

              $this->mCheckImageHeight = $height;

              return true;

       }

       //在验证码图片上逐个画上验证码

       function WriteCheckCodeToImage()

       {

              for ($i=0;$i<=$this->mCheckCodeNum;$i++)

              {

                     $bg_color = imagecolorallocate ($this->mCheckImage, rand(0,255), rand(0,255), rand(0,255));

                     $x = floor($this->mCheckImageWidth/$this->mCheckCodeNum)*$i;

                     $y = rand(0,$this->mCheckImageHeight-15);

                     imagechar ($this->mCheckImage, 5, $x, $y, $this->mCheckCode[$i], $bg_color);

              }

       }

       //输出验证码图片

       function OutCheckImage()

       {

              $this ->OutFileHeader();

              $this ->CreateCheckCode();

              $this ->CreateImage();

              $this ->SetDisturbColor();

              $this ->WriteCheckCodeToImage();

              imagepng($this->mCheckImage);

              imagedestroy($this->mCheckImage);

       }

}

$c_check_code_image = new CCheckCodeFile();

//$c_check_code_image ->SetCheckImageWH(100,50);//设置显示验证码图片的尺寸

$c_check_code_image->OutCheckImage();

?>

使用方法:

<tr>

      <td align="center" valign="middle">验证码</td>

      <td align="center" valign="middle"><input name="number" type="text" style="80px;">

      <img src="code.php" id="yzm" onclick="this.src='code.php?abc='+Math.random()" alt="图片看不清？点击重新得到验证码" style="cursor:hand;" />

</td>

    </tr>

验证是否正确

session_start();

  if($_POST["number"] == $_SESSION["code_str"]){

  //      echo("验证码正确");

  }else{

        echo "

                     <script>

                            var s=10;

                            function ok()

                            {

                            s--;

                            document.getElementById('tips').innerHTML=s;

                            if(s==0)

                            {

                            clearTimeout(t);

                            history.go(-1);

                            }

                            }

                            var t=setInterval('ok()',1000);

                     </script>

" . "请输入的验证码,请重新输入<span id='tips'></span>秒之后，将为您跳转到<a href="javascript:history.go(-1)">上一页</a>";

  }