I did something similar
the way I handled it was to have a vertically framed page. The left side was just decoration and held the JavaScript library. The main part of the page was the user interface and was composed by the JavaScript library. When the user made an update, the JavaScript validated the entries and sent the result to the server, the response from the server was essentially a set of JavaScript variable assignments with a call into the library code in the left part of the page. The assignments would happen and the library call would cause the user interface part of the page to be redrawn.
Does that explanation make sense? Does it fit your requirements?
