Access Local Filesystems
To be able to save files and folders from inside the web browser to the local hard drive you’ll need access to the filesystem. As this means a potential enormous security breach, it is not permitted by default. As a compromise between all or nothing, the FileSystem-API is only allowed to access a specific protected area on your local drive controlled by the browser. It is only this area, you will be allowed to read from and write to. It is not possible to access the whole of the local drive. Still you should be careful in implementing the technology thoroughly as trust will not be widespread, and for good reasons so.
The FileSystem-API can make use of local storage in two flavors. Storing can either be done temporarily, per session e.g. or files and folders can be stored permanently. Permanent storage does require the explicit permission by the user. This permission is requested by opening a tooltip below the URL bar, asking for confirmation.
Generally, to begin storing files, access to the filesystem needs to be established: