Good we have a community here. I’ve done that for you. 
It was not such a nice thing, because in JS you often miss some features, like even a simple MD5 implementation, (so good you did not try @z3ntu ) but now it works. I even added/had to add some unit tests and compared the results with the Perl version. (The tests are always run in your browser console as “self-tests” at the start.)
Also if you have some other test strings (IMEI, serial number and resulting expected code) I can use for testing, feel free to provide that. 
To be sure, I’ve deployed it at three different places, so you can decide which code/website to trust 
. (The best would be to just download the HTML file, verify that it does not do anything malicious locally and then open/use it.)
So here we are: In-Browser version of code generator (click on live version to use it directly in your browser)
- GitHub (live version)
- GitLab (live version)
- or the live version on Neocities (updated manually)