vijaythakor

I am developing a simple php website named : http://www.dopanchat.com In this site I used session to develop the login system, everything work fine but after some amount of time (for example, after 1 hour) the session expires automatically and user logged out from my site. I don't know if it's server problem or anything else. please help me to resolve this problem, you can check here : http://www.dopanchat.com