is there any free php code that, once installed, allows you to browse and edit files (with html, javascript, php and css highlight) on the server where it's installed? The aim is to code online, browser based. I've tried http://phpanywhere.net/ that can make this possible, but it is buggy and moreover it requires an external (ftp) access to your server that is quite different (and less secure) that working directly on the server.
Thanks in advance
There are a couple of reasons that this kind of thing might be a bad idea.
That said, I've seen it done before. For instance cPanel does it. Maybe you could look into some free cPanel alternatives like ISPConfig or EHCP. But I would be very wary of using something from someone you don't trust, for security reasons. Note that there are a lot of security problems that aren't solved by putting something behind SSL.