[btvquonq] Save content offline

Easy (I think) is to save to disk a snapshot of a web page's DOM as a static object.  Firefox's "Save Web Page, Complete" might already do this.

Doing this for Adobe Flash -- a snapshot of an active Flash object -- could be useful, but seems difficult, perhaps intense reverse engineering of the memory structures of the plugin. We don't want merely a raster, but a structured organization of vector objects before they get rasterized. Perhaps "Save As SVG."

Much harder is to save a page with active content, fully saving the active content not just a snapshot, even after making the assumption that the page author wants to let you do this.  I think we need standards.

Active sites often query a backend database on the server, so to save a complete active site requires downloading the entire backend database, as well as any frontend and middleware processing software that was on the server.  For example, we imagine a book that is displayed a page at a time, but the author wants to let the reader download the whole book to read offline on the web browser.