diff --git a/include/libwinevbs.h b/include/libwinevbs.h
index 3ba4df9..6cac7df 100644
--- a/include/libwinevbs.h
+++ b/include/libwinevbs.h
@@ -52,6 +52,14 @@ LIBWINEVBS_API const char* libwinevbs_hresult_name(HRESULT hr);
 typedef struct {
    void (*log)(libwinevbs_log_level_t level, const char* format, va_list args);
    HRESULT (*create_object)(const WCHAR* progid, IClassFactory* cf, IUnknown** obj);
+   /* Answers a VBScript MsgBox() call. Must return synchronously (its result
+      is used by the calling script statement immediately) - e.g. a real,
+      blocking confirm()/alert() call under Emscripten. type is the raw
+      VBScript "buttons" argument (MB_OK=0, MB_OKCANCEL=1, MB_YESNO=4, ...);
+      title may be NULL. Return the matching button id (IDOK=1, IDCANCEL=2,
+      IDABORT=3, IDRETRY=4, IDIGNORE=5, IDYES=6, IDNO=7), matching vbOK..vbNo.
+      If unset, MsgBox always answers IDOK/vbOK without asking anything. */
+   int (*msgbox)(const char* prompt, int type, const char* title);
 } libwinevbs_callbacks_t;
 
 LIBWINEVBS_API void libwinevbs_init(const libwinevbs_callbacks_t* callbacks);
diff --git a/src/libwinevbs.c b/src/libwinevbs.c
index 7b3d6f0..91091e4 100644
--- a/src/libwinevbs.c
+++ b/src/libwinevbs.c
@@ -32,6 +32,14 @@ HRESULT libwinevbs_create_object(const WCHAR* progid, IClassFactory* cf, IUnknow
    return CLASS_E_CLASSNOTAVAILABLE;
 }
 
+int libwinevbs_msgbox(const char* prompt, int type, const char* title)
+{
+   if (g_callbacks.msgbox)
+      return g_callbacks.msgbox(prompt, type, title);
+
+   return 1; /* IDOK/vbOK - no host callback registered, so just proceed */
+}
+
 const char* libwinevbs_hresult_name(HRESULT hr)
 {
    switch (hr) {
diff --git a/wine/dlls/vbscript/global.c b/wine/dlls/vbscript/global.c
index 0e0e144..351f967 100644
--- a/wine/dlls/vbscript/global.c
+++ b/wine/dlls/vbscript/global.c
@@ -33,6 +33,7 @@
 #include <locale.h>
 #include "scrrun_private.h"
 HRESULT libwinevbs_create_object(const WCHAR *progid, IClassFactory* cf, IUnknown** obj);
+int libwinevbs_msgbox(const char *prompt, int type, const char *title);
 extern HRESULT WINAPI WshShellFactory_CreateInstance(IClassFactory*,IUnknown*,REFIID,void**);
 #endif
 
@@ -2834,9 +2835,12 @@ static HRESULT Global_MsgBox(BuiltinDisp *This, VARIANT *args, unsigned args_cnt
         hres = show_msgbox(This->ctx, prompt, type, title, res);
 #else
     if(SUCCEEDED(hres)) {
-        char buf[2048];
+        char buf[2048], title_buf[256] = {0};
         WideCharToMultiByte(CP_ACP, 0, prompt, -1, buf, sizeof(buf) - 1, NULL, NULL);
+        if (title)
+            WideCharToMultiByte(CP_ACP, 0, title, -1, title_buf, sizeof(title_buf) - 1, NULL, NULL);
         libwinevbs_log(LIBWINEVBS_LOG_INFO, "vbscript: MsgBox prompt=%s", buf);
+        hres = return_short(res, libwinevbs_msgbox(buf, type, title ? title_buf : NULL));
     }
 #endif