Is there a web based terminal/ssh client?

If the Library is using Firefox and has the ability to install add-ons, try FireSSH - its a javascript based SSH client.

What you'll probably want to do, is to install a HTML-based terminal emulator. There are several (many) to choose from. That will give you a text field in a webpage (such as the one I'm currently typing into) and that will run on your system.

This is a list of such applications, in no particular order. I have little or no experience with these:

• http://anyterm.org/
• http://scott.yang.id.au/2006/04/ajaxterm-terminal-emulation/
• http://code.google.com/p/shellinabox/

You can see live demos of the three at the bottom of this page: http://anyterm.org/demos.html

All of these will work in any browser. Probably even IE4 :)

If you're on Google Chrome/Chromium, you could give Secure Shell a shot. It is a complete terminal emulator and a SSH client.
It and is developed by Google, and runs offline :)

Secure Shell is an xterm-compatible terminal emulator and stand-alone ssh client for Chrome. It uses Native-Client to connect directly to ssh servers without the need for external proxies.

You could also go with another extension, Devtools Terminal, which is a terminal emulator.

^{Note : This one requires a npm-install though. Details}

Happy SSHing :)