I did notice that "js" file - actually two of them:
openserenescreen.js
openserenescreenbuy.js
Yes. I don't know what generated the first one, or when the name changed, but they are identical and both take you to the same place:
http://www.serenescreen.com/
Footnote: as noted elsewhere, uninstalling MA3 does not get rid of any files from this folder.