This is a simple chatting application was created by Tuts+. Thanks to https://code.tutsplus.com/tutorials/how-to-create-a-simple-web-based-chat-application--net-5931, It helps me a lot. Also, thanks to InfinityFree app (a free web hosting website), I got my subdomain. But I have a problem which I also mentioned earlier in the InfinityFree forum, the time is always in GMT-4; but I live in the GMT+3, so there's always 7 hours diffrence between the post time (GMT-4) and real time here (GMT+3). This 'post time' or '.chat-time'code is in post.php
If you know the problem, please answer my forum question.