(I use Mozilla Firefox)

Go to Tools, Options... then turn off JavaScript. Then battle a Zedja depending on the Pokemon you're training. I'll use my Ghostly Sableye as an example I guess, but it knows Overheat. ;)

Anyway~! I would type in ZedjaFire (if Sableye didn't have that move, I would type in ZedjaDark or ZedjaGhost) and select Overheat. Then Attack! :3

After that, press F5 and Enter a bunch of times. This will refresh the winding lotsa times.

By doing this, you've beaten a Zedja in less than half a minute if done right.

The only annoying thing is that by turning off JavaScript, you can't access the tabs very easily and you can't decline offers etc.