You need the dan.html file, style.css, and script.js, or just clone the repository. To open, just open the dan.html file in your browser.
The program should be very similar to the MARS MIPS simulator, with a few differences. For loading and storing words, rather than calling something like 4($t1), the command is separated out into 3 sections, in a similar format to the other commands. The program loads with an example of most things, so that will help should what it looks like.
If you notice any bugs or things that might be nice to add in, let me know at tganderson0@gmail.com !