Server’s (PHP) and client’s (JavaScript) date & time

Server

Date/time : Thu, 17 Aug 2017 23:13:49 UTC/GMT
2017-08-18T01:13:49+0200 [ISO, local]
Time zone : CEST; Vienna, Austria [+2 hours to UTC/GMT]
UNIX Epoch: 1,503,011,629

Client

To get the time difference navigate to the Time Zone Converter.
In the 1^st pulldown menu [From Time Zone:] select [your location].
In the 2^nd pulldown menu [To Time Zone:]   select [Austria - Europe/Vienna].
Click Convert Time Now
See the Converter Results at the top of the page.
You have to calculate the time difference manually (first line – second line).Example:
Your local Date: February 02 2017; Time: 15:30:00
From [India - Asia/Kolkata] to [Austria - Europe/Vienna] gives
  15:30:00 Thursday February 2, 2017 in Asia/Kolkata converts to
  11:00:00 Thursday February 2, 2017 in Europe/Vienna
Hence, the time difference for your profile is 15:30 – 11:00 = +4:30.