“When you lookup a certain feature on caniuse.com, there’s an incredible assumption many of us make when interpreting its UI: given enough time, most everything goes green.”
alert, prompt and confirm have worked since the early web, and now they are in danger of deprecation. The web’s whole promise was that code written once keeps running. Evergreen browsers can take features away as easily as they add them. Developers now need a site to check whether yesterday’s features still work.