Also use pageshow event as URL change cue

[lmorchard]

In some navigation cases, the popstate event is not fired when URL
navigation happens. But, pageshow is. So, use that event as an
additional URL change cue.

[wraithgar]

Do we need both? Is pageshow more appropriate? A quick read of the description suggests we may be able to do this but it would need to be tested.

[lmorchard]

Honestly, I'm still trying to wrap my head around when each of these events fire across browsers. This fixed a bug for me, but it smells like a hack. I figured it's okay for now, because checkUrl stops duplicate work from happening if both popstate and pageshow both fire.

To reproduce the bug I was seeing, I did this in my app on Firefox:

• Load a page, navigate to another.
• Go to the URL bar, hit enter. The page reloads. (Just hitting the reload button doesn't do it)
• Navigate backward - nothing happens, because the popstate event doesn't fire. (But pageshow does)

What I haven't figured out yet is if pageshow fires at all the interesting times, and could be used to entirely replace popstate

[wraithgar]

Leaving both in would probably result in a lot of double-fires of the loadUrl method which is not good imo. And yes it looks like Firefox has popstate issues as per https://developer.mozilla.org/en-US/docs/Web/Events/popstate

Browsers tend to handle the popstate event differently on page load. Chrome (prior to v34) and Safari always emit a popstate event on page load, but Firefox doesn't.