[fallenspec]

It called progressive enhancement. You test whether you have a feature and then code around it if you don't.

e.g. When createObjectUrl was a new thing. I ended up doing something using AJAX and doing some processing server side for IE and Edge. Now I could have done all the processing server-side. However 80%+ of the users use Chrome. So instead of checking everything on the server, I could offload 80% of that to the browser.

[debaserab2]

"Coding around it" means handling an additional error state, which can be in varying degrees of complexity depending on what the feature is doing for your app.

[fallenspec]

Yes, obviously.. It really depends on how much time you have, what browsers they care about supporting etc.

There is a tooling out there to assist you and most of the compatibility issues are well documented now. 10 or so years ago when I started that really wasn't the case.