The File and Directory Entries API interface
FileSystem is used to represent a file system. These objects can be obtained from the
filesystem property on any file system entry. Some browsers offer additional APIs to create and manage file systems, such as Chrome's
This interface will not grant you access to the users filesystem. Instead you will have a "virtual drive" within the browser sandbox. If you want to gain access to the users filesystem you need to invoke the user by eg. installing a Chrome extension. The relevant Chrome API can be found here.