static v8::Handle<v8::Value> start1Callback(const v8::Arguments& args) { FeatureObserver::observe(activeDOMWindow(BindingState::instance()), FeatureObserver::WebAudioStart); if (args.Length() < 1) return throwNotEnoughArgumentsError(args.GetIsolate()); AudioBufferSourceNode* imp = V8AudioBufferSourceNode::toNative(args.Holder()); V8TRYCATCH(double, when, static_cast<double>(MAYBE_MISSING_PARAMETER(args, 0, DefaultIsUndefined)->NumberValue())); imp->start(when); return v8Undefined(); }