代码如下

$admin_pw="admin";//管理密码

$uploaddir="upload";//上传目录

session_start();

if($_GET['action']=="getcode")

{

setcode();

exit();

}

if($_POST['password']==$admin_pw && $_POST['yz']==$_SESSION['yzcode'])

{

$_SESSION['logined']=$admin_pw;

}

if($_GET['action']=="logout")

{

$_SESSION['logined']="";

header("location: ".$_SERVER['PHP_SELF']);

exit();

}

if($_SESSION['logined']!=$admin_pw)

{

?>

请登录

输入密码：

验证字符：

}

else

{

?>

文件上传

if($_POST['ac']=="upload")

{

$fileall=explode('.',$_FILES['file']['name']);

$filetype=$fileall[count($fileall)-1];

$filename=$uploaddir."/".$_FILES['file']['name']."_".rand(1,999999999).".".$filetype;

$fileexists=file_exists($filename);

while($fileexists==true)

{

$filename=$uploaddir."/".$_FILES['file']['name']."_".rand(1,999999999).".".$filetype;

$fileexists=file_exists($filename);

}

if(move_uploaded_file($_FILES["file"]["tmp_name"],$filename))

{

$url="http://".$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'];

echo "文件:".$filename." 上传成功！

文件地址：测试";

}

else

{

echo "文件".$filename."上传失败！";

}

}

?>

选择文件：

退出登录

}

function setcode()

{

Header("Content-type: image/gif");

$border = 0; //是否要边框 1要:0不要

$how = 4; //验证码位数

$w = $how*15; //图片宽度

$h = 20; //图片高度

$fontsize = 5; //字体大小

$alpha = "abcdefghijkmnopqrstuvwxyz"; //验证码内容1:字母

$number = "0123456789"; //验证码内容2:数字

$randcode = ""; //验证码字符串初始化

srand((double)microtime()*1000000); //初始化随机数种子

$im = ImageCreate($w, $h); //创建验证图片

$bgcolor = ImageColorAllocate($im, 255, 255, 255); //设置背景颜色

ImageFill($im, 0, 0, $bgcolor); //填充背景色

if($border)

{

$black = ImageColorAllocate($im, 0, 0, 0); //设置边框颜色

ImageRectangle($im, 0, 0, $w-1, $h-1, $black);//绘制边框

}

for($i=0; $i

{

$alpha_or_number = mt_rand(0, 1); //字母还是数字

$str = $alpha_or_number ? $alpha : $number;

$which = mt_rand(0, strlen($str)-1); //取哪个字符

$code = substr($str, $which, 1); //取字符

$j = !$i ? 4 : $j+15; //绘字符位置

$color3 = ImageColorAllocate($im, mt_rand(0,100), mt_rand(0,100), mt_rand(0,100)); //字符随即颜色

ImageChar($im, $fontsize, $j, 3, $code, $color3); //绘字符

$randcode .= $code; //逐位加入验证码字符串

}

$_SESSION['yzcode'] = $randcode;

Imagegif($im);

ImageDestroy($im);

}

?>