safeAjax is a jquery plugin a library and php ajax connector pair using JSON as the communications medium.
I wrote this plugin & connector pair to password protect web pages and safeguard my ajax communications and database actions from my web pages.
It's based upon chris shifletts article: the truth about sessions
Version 3 is a full client-side rewrite and updates/enhancements to the drop-in methodology (on the server side) supporting painless extentions of your server-side codebase.
Please read the wiki page for docs and usage and samples
The v3 alpha archive runs as a full demo, you can upload it to your site and run it as is.
Update: Version 3 is now in alpha state