No, it wouldn't be that. That can only prevent unload if it throws a native modal up (cousin of alert, confirm, prompt, etc).
I think what they must have done is push some URL to the history state, using the History API, to fuck with the back and forward buttons, enabling them to intercept when you navigate back, by having added an additional page in there, that you never visited, but that they can use to serve you this interstitial.
graderjs|3 years ago
I think what they must have done is push some URL to the history state, using the History API, to fuck with the back and forward buttons, enabling them to intercept when you navigate back, by having added an additional page in there, that you never visited, but that they can use to serve you this interstitial.
Just my 2c
smhg|3 years ago
That's a very "bold" choice of 538 if you ask me.
usmannk|3 years ago
You can see it if you right click the back button after navigating to the article.