That may be your viewpoint but browsers have historically always taken the other viewpoint. Take HTML parsing for example. You can miss closing tags and a ton o

That may be your viewpoint but browsers have historically always taken the other viewpoint. Take HTML parsing for example. You can miss closing tags and a ton of other stuff, and it'll all work on a best-effort basis. The browsers job is to do the best it can, that's what users want. No one would use a browser that breaks at the smallest tiniest error in the source code.