Obsolete since JSAPI 28
This feature is obsolete.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.

Replaced by JS::ToBoolean

Convert any JavaScript value to a boolean value.


JS_ValueToBoolean(JSContext *cx, jsval v, JSBool *bp);
Name Type Description
cx JSContext * The context in which to perform the conversion. Requires request. In a JS_THREADSAFE build, the caller must be in a request on this JSContext.
v jsval The value to convert.
bp JSBool * Out parameter. On success, *bp receives the converted boolean value.


JS_ValueToBoolean converts a specified JavaScript value, v, to a boolean value. It implements the ToBoolean operator specified in ECMA 262-3 §9.2. On success, JS_ValueToBoolean stores the converted value in *bp and returns JS_TRUE. On error or exception, it returns JS_FALSE, and the value left in *bp is undefined.

For versions greater than JSVERSION_1_2, all objects convert to JS_TRUE, even Boolean wrapper objects like the one produced by new Boolean(false). This is the behavior specified in ECMA 262-3 §9.2. See related discussion on Google Groups.

See Also