I don't know if Poser has a JavaScript API or not, to be honest.  I thought we were discussing a stand-alone item, with most people being dependent on the Python that comes with Poser.  (Although I just realized that if it IS a stand-alone app, then people could just download Python separately, and Poser could continue to cheerfully run on the version it comes with.  As far as I know, having multiple copies of Python isn't a problem.)

Although if using JavaScript let you run a stand-alone app in a browser, that would probably save a lot of work on a GUI for the thing . . .

Me not know.  Me just technician who dabble in programming.  Me use BASIC and ARexx a lot.