I've tested AjaxTerm for a while and it works well. For my case, I had problems with special characters on french keyboard (accessing "@" character is made by pressing AltGr+0). It wouldn't go in AjaxTerm. I had to use the paste button on the ajaxterm. But it wasn't working on my chromium version on Windows XP. So I had to launch IE7 puke.
So I gave a try to shellinabox and it is working fine. The paste work with CTRL+SHIFT+V and works on chromium Windows XP. I tried on my ubuntu even if I prefer using a real SSH in a term. It seems that some char doesn't work, but can't remember which.
Anyway, my problem was more accessing my box where ports are blocked, so I needed more on a Windows box.
I use shellinabox on localhost only with access from an Apache2 with Proxy redirections to the port of shellinabox. The localhost listening of shellinabox are on pure http. But the public access from web are in https with the connection handled by Apache2.