That's the crux of this whole argument, though: an unrecognized tag is not an error. Because Html tags are not instructions to be followed like an imperative program. They are semantic expressions of document structure, intended for a variety of potential clients of differing capabilities. Different browsers (and other devices) are free to interpret parts of those declarations they understand, and ignore others. Html documents can be full of tags and attributes, meant for specific clients, in different contexts.
By design, browsers are supposed to ignore anything they don't recognize. If they wrote errors to the console for every bit of unknown content, the console would be very noisy indeed.
This seems to be a hard concept for many to grasp.
Yes, and Firefox also writes warnings to the console for malformed content (known elements appearing in the wrong place, such as putting a tr element directly inside a div), mismatched open/close tags, etc.
So that should satisfy most of your concerns around mistyped html tags. The difference is that the browser won't just stop rendering the page, and in most cases the user can keep working even if something looks a little off.
But unrecognized tag and attribute names should not result in warnings in the browser. The browser has no idea whether these names might have meaning to other clients, and so it (rightfully) ignores them.
You can still catch all of these at dev/build time with an html validator. So there's much less need for console warnings if any kind.
But you don't really need that as much (or at all) with html.
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