history.popState return different event type in different websites in the same browser

history.popState return different event type in different websites in the
same browser

I am a noob of history pushState and popState, I am in the process of
implementing ajax history on 2 sites. Both of them are working fine using
the following code segment:
$(window).bind("popstate", function(event) {
console.log(event);
/* some logic */
});
except that one site's popstate returns a PopStateEvent and another site
returns v.Event
So for the second site I will need to check for event.originalEvent
instead of just checking event on the first site.