A small corner
of JavaScript history.

An API explorer for the familiar, the obscure, and the things you didn’t know were properties.

The original idea

browsersupport.io started as a way to look up any JavaScript property. Not just new language features, but vendor prefixes, deprecated APIs, and the everyday properties that rarely get a compatibility table of their own.

The lab collected property names from browsers, then checked for their existence across browser versions. That produced an archive of tens of thousands of properties, each with its own URL.

What the colors mean

Present means the detector found the property. Absent means the property, or something needed to reach it, was missing. Unknown means there’s no usable observation. A detection error is unknown, too.

These are shallow checks. They don’t establish that an implementation works correctly, or that it’s available under every browser setting. A test may also find inherited properties.

And today?

The site keeps those historical results accessible. Browser versions shown are the ones tested, not necessarily current releases. Original test dates weren’t recorded; new observations carry a timestamp. A property’s creation date isn’t its test date.

For current compatibility decisions, MDN and Can I use are useful companions. Build tools can transform syntax and supply some polyfills, but the browser still determines which APIs it exposes.

Still a personal project

Made by Dillon de Voor, kept around for curiosity and a little nostalgia. The source is on GitHub. Found something odd? An issue there is welcome.