FireFTP is a free,cross-platform FTP client for Mozilla Firefox. It is one of the most useful add-on for web developers. Some of its features are SSL/TLS/SFTP support, Keep directories in sync while navigating,20 languages, UTF8 Character Set Support, Automatic reconnect and resuming of tranfers, Search and Filtering, Integrity Checks of transfers (XMD5, XSHA1), Generate hashes of files (MD5, various SHA’s), Drag & Drop, File Compression: Using MODE Z, Proxy, FXP and IPv6 support.
Firefox add-on page:
Download fireftp from above links and restart your firefox.
To open fire ftp,
Go to Tools menu in firefox and click FireFTP.