It is possible to run it standalone, an archive is attached here.
A long time ago, I wanted to participate in the ThinkQuest contest together with one of my colleagues. We were preparing an entry about how computers work and we got it to look quite nice, but eventually we missed the deadline for uploading it (for some stupid reason, we got to the point where we were filling the forms).
Part of this project was a CPU simulation inside the web-page which I later further developed and fixed for browser compatibility. It simulates a processor which is somewhat of a simplified Z80 at machine code level and displays the internal workings by highlighting the internal elements that are activated by specific instructions.
I didn't touch this code in a long time, but it seems it still works even on the modern browsers. It used to have nicer hand-drawn "graphics", but i replaced it some time ago with a lower quality ones to speed up loading.