> What I really want is to somehow tell the browser "if the current window URL is about to change via this anchor element, call this function instead".
This is pretty doable using javascript - just register an onclick on the <a> tag and have your event handler cancel the default navigation behaviour. Your website will then continue to work great even if the user has javascript disabled. And all the built in browser behaviour (like the right click "link" menu, and ctrl+click) still works perfectly.
That said, this is a pretty obscure "trick". It would certainly be nice if the DOM API made this easier to do.
Is there really anything easier to do? If you're disabling the default event, you're doing it to provide some other functionality, which is necessarily going to involve writing a function to attach to a handler, and adding event.preventDefault() at the top is about as easy as it gets. Anything easier would involve eliminating the attached handler, which doesn't make a lot of sense.
Also, .preventDefault() wasn't obscure in the jQuery era; if it's obscure now that's a sad commentary.
In my experience in this case you need to explicitly filter out middle-click, ctrl-click, cmd-click and whatever other features the browser may offer. Otherwise you will accidentally prevent them too. I would love if there was a more specific event that avoided this problem.
This is pretty doable using javascript - just register an onclick on the <a> tag and have your event handler cancel the default navigation behaviour. Your website will then continue to work great even if the user has javascript disabled. And all the built in browser behaviour (like the right click "link" menu, and ctrl+click) still works perfectly.
That said, this is a pretty obscure "trick". It would certainly be nice if the DOM API made this easier to do.