What is the requirement of session_start()?
Should I call this function on every HTML page or only on main page?
the best way to avoid problems with the session_start. it's put it before the <!doctype> of your page and include the doctype into all the others pages
yeah you can when you need to run your each script,function or program
session_start() call is compulsory when you need to use a session. you need to specify it in every page you use.
session_start are used to applying the session in a php code that mean we r starting the session , or in other hand session_destroy use for destroy the session.
yes can do it more as you like