PHP to see if the message has been read

When you are sending a message, you may be wondering if the email has been read by the other person. Here's a very interesting piece of code that shows the actual date and time that the other IP address records the read.

4. error_reporting (0);
6. Header ("Content-type:image/jpeg");
10. Get IP
12. if (!emptyempty ($_server[' http_client_ip '))
14. {
16. $ip =$_server[' http_client_ip '];
18. }
20. ElseIf (!emptyempty ($_server[' http_x_forwarded_for '))
22. {
24. $ip =$_server[' http_x_forwarded_for '];
26. }
28. Else
30. {
32. $ip =$_server[' remote_addr '];
34. }
38. Time
40. $actual _time = time ();
42. $actual _day = Date (' Y.m.d ', $actual _time);
44. $actual _day_chart = Date (' d/m/y ', $actual _time);
46. $actual _hour = Date (' h:i:s ', $actual _time);
50. Get Browser
52. $browser = $_server[' http_user_agent '];
56. LOG
58. $myFile = "Log.txt";
60. $fh = fopen ($myFile, ' A + ');
62. $stringData = $actual _day. ' ' . $actual _hour. ' ' . $ip. ' ' . $browser. ' ' . "\ r \ n";
64. Fwrite ($FH, $stringData);
66. Fclose ($FH);
70. Generate Image (Es. Dimesion is 1x1)
72. $newimage = Imagecreate (1,1);
74. $grigio = Imagecolorallocate ($newimage, 255,255,255);
76. Imagejpeg ($newimage);
78. Imagedestroy ($newimage);
82. ?>

how PHP sends messages