Concrete5 is an open source content management system. It supports JavaScript and jQuery. It’s intended users are designer/developers who have a good grasp of HTML/PHP and who want more control over what is possibly to be edited for content editors themselves.
Used by designers/developers who wish to create a templates or editing interfaces to be handed off to a client to use and update on their own. Although Concrete5 can be used by client-site editors through its in-context editing feature, it is not simply a WYSIWYG web tool. The system’s “flexible architecture” enables developers to create custom applications for clients to use as tools or functions to edit their website. That being said, it is not a ‘lightweight’ system - using it for basic content management would be under utilizing the system.