index.php(实现输入验证码页面)代码如下： Code代码如下: <html>
<head>
<title>check code</title>
</head>
<body>
<form name=check method=post action=check.php>
<input type=hidden name=init value=1>
验证码：<input type=text name=code maxlength=4 style="width=50px;">
<!--得到验证码图片-->
<img src=image.php>
<p>
<input type=submit value="提交">
</form>
</body>
</html> image.php（验证码生成页面）代码如下： Code代码如下: <?php
session_start();
srand((double)microtime()*1000000);
$authnum=rand(1000,9999);
session_register("authnum");
header("content-type:image/png");
function creat_image( $width, $height, $authnum)
{
srand((double)microtime()*1000000);
$im = imagecreate( $width, $height);
$black = ImageColorAllocate( $im, 0,0,0);
$white = ImageColorAllocate( $im, 255,255,255);
$gray = ImageColorAllocate( $im, 200,200,200);
imagefill( $im,0,0, $gray);
//将四位整数验证码绘入图片
imag
