Session vs. Post

[dfatphpb]

Is it more efficent to start_session to pass data around via $SESSION or just post and use $POST ?

[NogDog]

Posting it would mean that the client would have to upload the data on each page request and download it on each reply, adding to the internet lag time. For small amounts of data this would be negligible and might not be much different from storing it in the session data for overall response time; so in that case I would go with whatever makes more sense for the way you want to design your application and keep it easy to maintain. For large amounts of data I would stick with sessions rather than repeatedly moving that data back and forth across the 'net.

[Weedpacket]

Another cause of drag when using $_POST is the necessity of revalidating the data every time it gets sent back to the server - because unless you have very good control over what the client is doing, it could be doing anything to the data.

[mpb001]

POSTS/GETS - Guaranateed that the data sent is directly to do with the changing page( ie. tab safe )
SESSIONS/COOKIES - Global data that does not have to be tab safe.

Tab safe means if I go to a page, open a new one in a new tab then go back to the original screwy things don't start happening due to it thinks I am still using the other tab/window.