diff -ruN a/platform/emscripten/OsEmscripten.cpp b/platform/emscripten/OsEmscripten.cpp
--- a/platform/emscripten/OsEmscripten.cpp
+++ b/platform/emscripten/OsEmscripten.cpp
@@ -36,7 +36,8 @@
 
     virtual std::string userDataDir()
     {
-        return "/no/user/data/dir/on/emscripten/";
+        /* the page keeps this folder in the browser (IndexedDB) */
+        return "/home/web_user/.numptyphysics";
     }
 };
 
diff -ruN a/src/Dialogs.cpp b/src/Dialogs.cpp
--- a/src/Dialogs.cpp
+++ b/src/Dialogs.cpp
@@ -225,7 +225,9 @@
     text->alpha(100);
     scroll->add(text,0,0);
     vbox->add( scroll, 0, 1 );
+#ifndef __EMSCRIPTEN__
     vbox->add( new Button(Tr::copy(PROJECT_HOMEPAGE),Event::SELECT), 36, 0 );
+#endif /* a web page cannot open the browser */
     m_content->add(vbox,0,0);
   }
   bool onEvent(Event& ev)