Obsolete since JSAPI 32
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.
Indicates whether a JS value has a type that is subject to garbage collection.
Syntax
JSVAL_IS_GCTHING(v)
Description
JSVAL_IS_GCTHING(v) is true if the jsval v is either JSVAL_NULL or a reference to a value that is subject to garbage collection. JavaScript performs automatic garbage collection of objects, strings, and doubles.
This macro exposes JavaScript engine implementation details and usually isn't what the application really means. See jsval for alternatives.