Are you looking for a tool which will let you upload your files using Firefox in FTP server ? Here is a better solution:
Upload Files Using Firefox
If you are a Firefox user and a Firefox fan, and you want to upload files within Firefox, instead of using any other software, then you should simply download FireFTP, a plugin of Firefox. It will let you manage your FTP files, where you can upload, download your files, within the environment of Firefox.
No matter which operating system you are using, if you’re using Firefox, simply check out the following post to download and install FireFTP in Firefox: