web api instance property
KeyboardEvent: keyIdentifier property
The deprecated KeyboardEvent.keyIdentifier read-only property returns a “key identifier” string that can be used to determine what key was pressed. Its non-deprecated replacement is key.
Specifications
Not part of any current specification. This property was part of an old draft of the DOM Level 3 Events Specification, but it was removed in later drafts in favor of key.
Browser compatibility
Browser compatibilityCompatibility data is available on the canonical MDN page.