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Caption
Web dev: What browser is visiting the page?
User agent string:
A screenshot of a browser. The URL bar reads firefox://settings, a button on the URL bar is labelled Netscape, a popup from the button reads: "You're viewing a secure Opera page", and the web page title reads "Chrome settings".
Functionally useless. With the web standardized, we shouldn't need user agents anyway. It would be more beneficial to ask "do you support X, Y, and Z?"
It's called feature detection and it goes a long way back, even before Modernizr popularized it.
Popularized? That gets less than 100k downloads a week
Most developers just write their own feature checks (a lot of detections are just a single line of code) or use a library that polyfills the feature if it's missing.
The person you're replying to is right, though. Modernizr popularized this approach. It predates npm, and npm still isn't their main distribution method, so the npm download numbers don't mean anything.
Neat, thanks for clarifying! I’ve never heard of it
It used to be huge.
That's exactly what you're supposed to do with the modern web, via feature detection and client hints.
The user agent in Chrome (and I think Firefox too) is "frozen" now, meaning it no longer receives any major updates.
I know Safari 15.3 doesn’t support feature Y, but I also know the current version does. Now I want to know if I can just use the feature or if I need to program around Safari 15.3. It would be nice to just look at the server logs from last month and see if someone still uses it.