In retrospect it seems he could have saved himself a Fiddler session if he just opened console debugger in browser and used `?"-(function(){debugger}())-"` in U

In retrospect it seems he could have saved himself a Fiddler session if he just opened console debugger in browser and used `?"-(function(){debugger}())-"` in URL instead of `?"-prompt()-"`. (I would not have guessed this either, but may come handy next time.)