图形数字验证代码 Code:   <?

/*

* Filename: authpage.php

*/



srand((double)microtime()*1000000);



//验证用户输入是否和验证码一致

if(isset($_POST['authinput']))

{


if(strcmp($_POST['authnum'],$_POST['authinput'])==0)

echo "验证成功！";

else

echo "验证失败！";

}



//生成新的四位整数验证码

while(($authnum=rand()%10000)<1000);

?>

<form action=authpage.php method=post>

<table>

请输入验证码：<input type=text name=authinput style="width: 80px"><br>

<input type=submit name="验证" value="提交验证码">

<input type=hidden name=authnum value=<? echo $authnum; ?

<img src=authimg.php?authnum=<? echo $authnum; ?

</table>

</form>

-------------------------------------------------------------------------------------------------------------

<?
/*

* Filename: authimg.php

*/
//生成验证码图片
Header("Content-type: image/PNG");

srand((double)microtime()*1000000);

$im = imagecreate(58,28);

$black = ImageColorAllocate($im, 0,0,0);

$white = ImageColorAllocate($im, 255,255,255);

$gray = ImageColorAllocate($im, 200,200,200);

imagefill($im,68,30,$gray);



//将四位整数验证码绘入图片

imagestring($im, 5, 10, 8, $HTTP_GET_VARS['authnum'], $white);



for($i=0;$i<50;$i++) //加入干扰象素

{

imagesetpixel($im, rand()%70 , rand()%30 , $gray);

}



ImagePNG($im);

ImageDestroy($im);

?>