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RegisterJSListener

Since: IVPrismaUI1

virtual void RegisterJSListener(
    PrismaView view,
    const char* functionName,
    JSListenerCallback callback
) noexcept = 0;

Exposes a C++ callback to JavaScript. After registration, calling window.functionName(arg) from JS invokes the C++ callback.

Parameters​

  • view - Target view handle.
  • functionName - The name JS will call as window.functionName(arg).
  • callback - Receives the single string argument passed from JS.

Threading​

Dispatched onto the main game thread - the framework wraps every RegisterJSListener callback in its own F4SE::GetTaskInterface()->AddTask before it reaches your code. RE::* access, InteropCall/Invoke calls, and any other game-thread work are safe to do directly inside the callback; no manual dispatch is needed.

BindUIEvent (V4) makes the same guarantee as part of the API's actual contract rather than as a detail of the current backend - prefer it for new code, but existing RegisterJSListener usage is not a bug and does not need to change.

Best practice​

Register listeners inside your OnDomReadyCallback (see CreateView), so they exist before any JS on the page could call them.

Example​

// C++ - register in OnDomReady
api->RegisterJSListener(view, "onCloseRequest", [](const char* /*arg*/) {
    g_api->Unfocus(g_view);
    g_api->Hide(g_view);
});
// JS - call from the page
onCloseRequest();

See also​

BindUIEvent (V4), InteropCall, Invoke.