iOS显然是永久缓存网页

Question

I changed my website at the beginning of March to use php instead of shtml. I put server-side redirects in place, and my analytics showed almost everyone picking up the php versions within a couple of days. The only devices that went on and on showing as .shtml were all iOS, but even that seemed to stop after a week or so. However, I have just now seen a .shtml usage come up on an iOS 10.3.3 tablet running Safari 10.0. How can this be happening? Surely no browser is going to cache a page for over 40 days? There were no special cache settings on the old shtml pages. Any ideas gratefully received. Thanks Mandy

Answer 1

From the comments:

iOS seems to keep tabs open indefinitely now, and just suspends the page as if it were an app. It's possible that the person with the tablet just hasn't visited your page in a couple months, discovered the tab while scrolling through them, and re-opened it. The browser MIGHT try to do a reload, but if it doesn't, they may have just tried to navigate inside a stale version of your app