How to manage cookies - with JavaScript or with HTTP Set-Cookie?
Cookies are always bundled with the HTTP header, so there is no 'improvement' in reading via JavaScript and sending them via AJAX to the server. 
For example, display-related settings such as font-size or website language are usually only relevant for the client-side, so I'd simply use JavaScript to set and retrieve such cookies.
Stuff like a session ID requires server-side work anyway, so maintaining the cookie via HTTP Set-Cookie seems to be the most straightforward way to do it.
I am creating a web application within GAE environment. It heavily uses AJAX/JSON to send/receive data and all about that. I don't worry much about browsers with JS disabled and obsolete browsers as it's my personal project and I am trying to make it simple and not bloated in code. So, I use JavaScript heavily in the project. Please advise me how to manage cookies and sessions in that case better. I have two variants - use HTTP Set-Cookie where possible and JavaScript where it's not. The second is opposite - use JavaScript where possible. Both variants work fine now but I want to make it right way. With JavaScript scenario when there a cookie needs to be set, I get some data over AJAX with some keys, then with a jQuery plugin set these keys to cookies and vice versa, read cookies with JS and send them over AJAX. What a re pros and cons of both methods? Thanks!