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This feature is obsolete.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.
Determines if a given jsval is a JavaScript boolean.
Syntax
JSVAL_IS_BOOLEAN(v)
Description
JSVAL_IS_BOOLEAN(v) is true if the given JavaScript value, v, is a boolean value (that is, it is either JSVAL_TRUE or JSVAL_FALSE).
To convert between JavaScript boolean values (jsval) and C boolean values, use JSVAL_TO_BOOLEAN and BOOLEAN_TO_JSVAL.