PHP 实现查看邮件是否已被阅读

查看邮件是否已被阅读：当你在发送邮件时，你或许很想知道该邮件是否被对方已阅读。这里有段非常有趣的代码片段能够显示对方IP地址记录阅读的实际日期和时间。 经测试代码如下：

<?PHP
error_reporting(0);
Header(Content-Type: image/jpeg);

//Get IP
if (!empty($_SERVER['HTTP_CLIENT_IP']))
{
  $ip=$_SERVER['HTTP_CLIENT_IP'];
}
elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
{
  $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
}
else
{
  $ip=$_SERVER['REMOTE_ADDR'];
}

//Time
$actual_time = time();
$actual_day = date('Y.m.d',$actual_time);
$actual_day_chart = date('d/m/y',$actual_time);
$actual_hour = date('H:i:s',$actual_time);

//GET browser
$browser = $_SERVER['HTTP_USER_AGENT'];
    
//LOG
$myFile = log.txt;
$fh = fopen($myFile,'a+');
$stringData = $actual_day . ' ' . $actual_hour . ' ' . $ip . ' ' . $browser . ' ' . \r\n;
fwrite($fh,$stringData);
fclose($fh);

//Generate Image (Es. dimesion is 1x1)
$newimage = ImageCreate(1,1);
$grigio = ImageColorAllocate($newimage,255,255);
ImageJPEG($newimage);
ImageDestroy($newimage);

/*** 以上代码来自：编程之家 jb51.cc（jb51.cc） ***/ 
?>