AJAX single-page map-based data entry interface

I require a single-page AJAX interface. The page will consist of a google map as its base, with a single pop-up form for viewing/entering information about specific locations on the map. Onload: * load the google map (it can fill the screen) * load KML data from a feed URL * plot KML data on map (using google's map api) * center and zoom map to user's current location (obtained using map api --> W3C and google gears methods) * pre-cache detailed data for nearest ~10 markers to user's location * Uses GET requests: [login to view URL][unique location id from kml]/detail * Data is returned as JSON When user selects a location marker: * pop-up a half-screen form for that location * Form is pre-populated with data for that location (from the cache if possible) * Fields can be of certain types: * 2-state buttons: can be in a visually pressed or not-pressed state (clicking on them toggles their state) * grouped buttons: as above, but a group of 2 or more buttons only one of which can be pressed * "tag" fields: user can add or remove text tags (see tagging interface for [login to view URL]) * text fields * Fields are fixed in the application When user updates information in the form: * updates to fields should be sent via GET requests * [login to view URL][location id]/[field name]?[new value] * UI elements should reflect change only on successful update (HTTP 200) * If update fails or times out, UI should cache update, make other UI elements read-only, and display a msg to the user at the top of the screen "Updating information is temporarily not possible. Will re-try soon." * UI should retry the cached update every 5 seconds. If succeeds, update UI elements, remove read-only lock, and remove usr msg. Coding to be performed on github, with deliverables zipped and uploaded to VWorker for record-keeping.