As with any new web technology, the question of browser support is often a determining factor for widespread use by web developers.
The good news is that the latest versions of the mobile web browsers support offline applications along with some very early releases of many desktop browsers.
In this context, “application files” include static HTML pages, CSS files, images and scripts as well as server processed pages or files.
The manifest only cares about the resulting file as served to the browser. Any file listed in the manifest file that does not appear under any other section heading is assumed to be a file to load into the application cache.
When connected to the web, the manifest is checked for updates and any new versions of the application’s files are downloaded in the background for the next visit to the page.