Obsolete since JSAPI 24
This feature is obsolete.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::ToNumber.

Convert any JavaScript value to a floating-point number of type jsdouble.


JS_ValueToNumber(JSContext *cx, jsval v, jsdouble *dp);
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.
dp jsdouble * Out parameter. On success, *dp receives the converted floating-point value.


JS_ValueToNumber converts a JavaScript value to a number. It implements the ToNumber operator described in ECMA 262-3 §9.3.

On success, JS_ValueToNumber stores the converted value in *dp and returns JS_TRUE. On error or exception, it returns JS_FALSE, and the value left in *dp is undefined.

See Also