The GP is talking about a different API: https://developer.mozilla.org/en-US/docs/Web/API/File_System_API https://developer.mozilla.org/en-US/docs/Web/API/File

The GP is talking about a different API: https://developer.mozilla.org/en-US/docs/Web/API/File_System_API https://developer.mozilla.org/en-US/docs/Web/API/File_System... This is one that Firefox refuses to implement (a personal gripe for me)