The Interop Project is a cross-browser initiative to improve web compatibility in areas that offer the most benefit to both users and developers. The group, including Apple, Google, Igalia, Microsoft, and Mozilla, takes proposals of features that are well defined in a sufficiently stable web standard, and have good test suite coverage. Then, we come up with a subset of those proposals that balances web developer priorities (via surveys and bug reports) with our collective resources. We focus on ...