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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”.
It’s called feature detection and it goes a long way back, even before Modernizr popularized it.
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.