v156 · @property

Descriptor lab

Build an @property registration by choosing which descriptors to include, then register it for real. The verdict below is what this browser did with it — accepted, or thrown out for being incomplete.

Compose a registration

The rule you built

Registration
not attempted
Computed value
—
With no author value
—
var() fallback used?
—

Applied to a real element

Choose descriptors and press Register.

code path

// An incomplete registration fails in two different ways before
// Chrome 156, and it is worth knowing which is which:
//
//   omitted `inherits`      -> TypeError, from WebIDL: it was a
//                              REQUIRED dictionary member
//   omitted `initial-value` -> SyntaxError, from the API: a typed
//                              syntax had to have one
//
// Chrome 156 accepts both.
try {
  CSS.registerProperty({ name, syntax: "<length>" });
  console.log("[@property] accepted with syntax only");
} catch (error) {
  console.warn("[@property] rejected:", error.name, error.message);
}

see also