Chris’ Corner: Browser Feature Testing

It’s interesting to me to think about during a lot of the web’s evolution, there were many different browser engines (more than there are now) and they mostly just agreed-on-paper to do the same stuff. We focus on how different things could be cross-browser back then, which is true, but mostly it all worked pretty well. A miracle, really, considering how unbelievably complicated browsers are.

Then we got standards and specifications and that was basically the greatest thing that could have happened to the web. So we put on our blue beanies and celebrate that, which also serves as a reminder to protect these standards. Don’t let browsers go rogue, people!

Then, still later, we actually got tests.

In retrospect, yes, obviously, we need tests. These are now web-platform-tests (WPT), and they help all the browser engines make sure they are all doing the right thing. Amazing.

(Side note: isn’t it obnoxious how many billions of dollars goes into newfangled browsers without any of them contributing or funding actual browser engine work?)

I only recently just saw browserscore.dev by Lea Verou as well. Yet another tool to keep browsers honest. Frankly I’m surprised how low all browsers score on those tests. I read in one of Lea’s commit messages “We’re not WPT, we’re going for breadth not depth.” which I found interesting. The Browser Score tests run in the browser and pretty damn fast. I haven’t run them myself, but I have a feeling WPT tests take… a while.

How can we improve on all this? Well a gosh-darn excellent way to do it is what the companies that make browsers have already been doing for a number of years: Interop. Interop is a handshake deal from these companies that they are going to get together and pick some great things that need better testing and fixed up implementations and then actually do that work. Interop 2025 looks like it went great again.

It’s that time again now, and these browser companies are asking for ideas for Interop 2026. If you have something that bugs you how it works cross-browser, now is a great time to say so. Richard has some great ideas that seem like perfect fits for the task.

Godspeed, ya’ll. We can’t all be like Keith and just do it ourselves.