It’s possible to have a set of sophisticated web software development tools for your desktop, completely free, both for the Linux platform as well as Windows. I’ve used them for a long time now, and although I’ve been coding primarily in php, these tools will work just as well with other languages…
Komodo Edit: This is an exceptionally good IDE since it debugs automatically while you add or modify your code. It supports a wide variety of programming languages, including php, perl and C++. You can get it from the Activestate website. Note that in some cases, such as with php, you need to also have the actual language’s interpreter installed.
Putty (Windows only): A very nice ssh client. The Linux version isn’t nearly as good, but using your shell directly with openssh is more than fine. Get it here.
Filezilla: A very handy sftp client. Get it here.
Gimp: If you need to edit or create images, nothing compares to this very complete graphics editor. Get it here.
That said, any serious code slinger who creates web interfaces should test the output on all popular browsers: MSIE,Firefox,Chrome,Safari and Opera. Ideally, you’ll also have older versions of each installed, as page rendering can vary quite a bit from one release to the next.
An even more advanced development environment can be had by setting-up a web server to run directly on your PC, but that’s a topic on its own…
