In this time also out on the normal internet, I've seen a shocking number of sites with critical functionality broken on safari. I'm talking nav, login, payment, on the sites of major brands, wireless carriers, saas companies.
So, do we face this challenge today? It exists certainly, but it seems like increasingly we are pretending it doesn't.
The only exception is 100vw and 100vh. On desktop, building an “app” that fills the screen with a header on top and a footer on bottom, this works great. On some mobile browsers, it places the footer below the browsers navbar because the navbar is not subtracted from the pages height.
I’ve had a heck of a time working around this in css, particularly because the fix for mobile seems to break desktop chrome.
But compared to even a decade ago, this is nirvana.
To test on Safari, you need a mac. That is a substantial cost. We assume it doesn't exist because we work at places that offer us macbooks (of note, all my teammates test on Safari because we easily can now), but when we are talking about the web at large this is a tremendous cost and is why so many websites are broken on Safari-exclusively (as opposed to both Safari and Firefox). So many websites, even from large companies, are developed by a handful of people, and their habits carry over. This establishes an expectation of not caring about Safari and all of its quirks, it gets relegated to "the user will just use another browser if it's broken".
For this problem to cease existing, Safari needs to be released on other operating systems. Until then, Safari will always be disregarded and untested.
Indexed DB LocalStorage Media keys SessionStorage Service Worker registrations and cache
Unless if the Web Applications was added to the Home Screen.