It looks like since this post was put up, that Wix have made it so much easier to add javascript to websites. Whether that be custom (as appears to be the case in this thread, or more standard (e.g. adding Google Analytics), Wix have come up with the goods to make it possible. Have never posted here before (so unsure on the rules) but we’ve done a 11 step guide on how to add javascript, which will hopefully be useful to people - How to add javascript to Wix websites - A1WebStats