I have a problem with iOS 15.4 which also occurs in iOS 15.4.1 and 15.5b2.
It turns out that I have a website that when opening a new window, after a few seconds, both the original web page and the new window freeze, no errors appear in console, I don't see any error reports, both pages just freeze completely and it doesn't do anything. nothing more.
I've tried to debug it with my Mac, but it doesn't indicate anything at all, it just hangs around doing nothing.
If I enter an alert in the debug console it doesn't execute it, it lets me type but doesn't press enter.
I've been with this for days and the truth is that I don't know where to look.
I have tried in Safari, Chrome (iPad 8th generation with iOS 15.4.1 currently) and there is no way.
The only way to make it work is to copy both urls (opener and window) and paste them in a new tab, close the frozen ones and then everything works normally, I can now open new windows and it doesn't fail again, it only happens the first time that I open a window since I have logged in.
When both tabs are frozen (opener and opened), I can open other tabs and browse normally as if nothing happened, only those two are frozen, I suppose that since they are related both are affected.
Any ideas what I can look at?
I am new to the mac environment and I don't know if I am not looking at the logs that are required, I understand that it is the webkit (common to all browsers on iPad).
In previous versions of iOS it works perfectly and without problems.
Any suggestions would be welcome.
I've already solved it, what a madness.
It turns out that I have a landing page where you log in to an intranet(opener) that opens a book(opened) and after a few seconds both the opener and the opened just froze, if you copy and paste their urls in a new tab or I reloaded the opener, everything worked perfectly until the session was started again, which froze again.
Comment that in the book, Animate (createjs) is used a lot and it is possible that it is a matter of the conjunction of both products.
I had another landing from which I could login and none of this happened, and it turned out that in the landing that freezes I had a YouTube video without a posterframe, so I guess it preloads the video (I see a loop of calls to youtube, without touching the video) and this is what then freezes both the intranet (which is loaded where the landing page was before) and the open book from the intranet.
It was enough for me to put a posterframe on the landing and everything works as it should.
Thank you all for the invaluable help, I have not seen any error log anywhere that could make me think of this big mess because of a video that is on a previous page.
Of course this does not happen in versions of iOS prior to 15.4 (or Safari prior to 15.4), and I still can't explain how it can happen, at least it will serve as a clue for someone.