A webmin that has a file manager to manage files on server.The file manager must be implemented using a non-java tech as my browser won't support java
I personally have used Responsive Filemanager and found it to be pretty good.
Sure it does have some limitations: i.e. it is not an FTP client and AFAIK you can't modify file permissions with it.
Despite that for what it is it is quite powerful, and very UI friendly. It has a Java option but that is not required (nor default) and the non-Java uploader's only limitation is a size maximum of around 50mb.
Responsive Filemanager has a whole lot of extra image specific features (like auto-thumbnai generation) but it is pretty good for everything else as well: - drag and drop uploading - drag and drop moving of files in the directory(ies) that it can access (which is highly configurable) - copy and paste actions - lots of (fast) filtering and sorting options