Internet Explorer is dead (ok, is a Zombie. But was supper-seeded by Edge for most users).
Safari is sadly not yet supported.
The nice thing is that you can employ security enhancements based on this technique even if it's not supported by all your clients.
I.e. you can automatically reject requests if the headers are given and have a bad value, which would add additional protection against certain attacks for all users except the ones stuck on IE or Safari.
1. it was largely dominant, so people thought they could develop just taking that browser in consideration
2. for the previous point, MS started to develop proprietary features (like ActiveX)
3. at a certain point its development was stopped for a long time
Safari certainly cannot match the first two reasons. But it cannot match the third either, because the development of standard web features is going on at good pace (see <https://webkit.org/status/>).
1. It doesn't support many of the latest web standards
2. A large enough percentage of users use it that it can't be simply ignored
Both of those points apply to modern Safari. Less so to IE these days as #2 becomes less and less applicable; hence "Safari is the new IE".
> Safari certainly cannot match the first two reasons.
1. Most users view websites on their phones. Safari is the only browser on iPhone (there are other browser skins, but they're all forced to run on top of Safari). The market share of iOS devices is usually about at least 50% in developed nations.
2. iOS has proprietary features, it is known as the App Store. If you want to develop certain things, you must use the app store, the browser is locked out of those features (even if all other browser vendors have them).
> But it cannot match the third either, because the development of standard web features is going on at good pace (see <https://webkit.org/status/>).
3. I probably don't need to go into this point since it's common knowledge that Safari has always been the least compliant browser in terms of web standards. Their history of holding back features or implementing features with critical flaws that make them useless has been a recurring trend for the last decade. Just because they have checked a box on a table, doesn't mean the feature is anything close to useable.
Because I use Safari specifically for privacy reasons and it also used to never trigger my fans to full speed just to play videos, like Chrome. I also have read that while Safari does tend to take longer, their implementations tend to be more polished. But this was more like a tweet so take that anecdata with a grain of salt.
Today I spent hours debugging why pages with a particular iframe embed would log you out of the parent site on Safari / iOS. Possibly because the same first-party resource was requested from both outside and inside the frame? Not sure yet.
If you attempt to use localStorage from a private tab on safari, it reports that it's present and working, but raises an exception on any access (every other platform either does not expose localStorage in private tabs, or clears it after).
Also more user-friendly way to install desktop shortcut would help tremendously to make web apps more popular. Of course Apple is not interested with that, but it's still sad.
It's defense in depth :D
I think you meant superseded (pronounced super-seeded).
