FWIW, I asked this since I've built client-side ads/analytics code before and I very much prefer JS-based solutions, since you can sort out the difficulties of

FWIW, I asked this since I've built client-side ads/analytics code before and I very much prefer JS-based solutions, since you can sort out the difficulties of dealing with interfering scripts once, put it in a library and still have control of what is going on. But I guess it does provide a simple mechanism for folks who would otherwise use a redirect and don't want to deal with the complication, so thanks for the insight.