Log files that an end-user or maintainer might want to see should be stored someplace in the normal file system. While the checked answer suggests how to find them when the HTML5 API is used, this location is subject to change and is troublesome to find. File and Directory Entries API. The Firefox implementation of the File and Directory Entries API is very limited; there is no support for creating files. Only for accessing files which are selected by the user in a file element (see HTMLInputElement as well) or when a file or directory is provided to the Web site or app using drag. Oct 14, · HTML5 File API is used to access files on the client machine via web browsers. There are 3 levels of File APIs in HTML5 standards: File API (Let me call it as File Reader API) File API: Writer (also called as File Writer API) File API: Directories and System (also called as File System API)5/5(18).