Li-Ri 3.1.6 for fredygames.com (GPL-2.0-or-later or GPL-3.0, like the game). Every change is active only
when building with Emscripten (__EMSCRIPTEN__):

- menu.cc: Sleeping() yields to the browser (emscripten_sleep(0)) when a frame is late, so the game's own
  loops never block the page (the build uses Asyncify; SDL_Delay already yields otherwise);
- menu.cc, main.cc: the window is a fixed 800x600 canvas, never fullscreen (the page scales it and has
  its own fullscreen button), so the fullscreen option does nothing;
- main.cc: fredygames_save(), which the page calls when the tab is hidden or closed: the game only writes
  li-ri.ini (options, unlocked levels, high scores) on exit;
- sprite.cc: language files other than English are downloaded on demand from lang/<name>.gz next to the
  page and decompressed with DecompressionStream, instead of being preloaded (about 6 MB each).

diff --git a/src/main.cc b/src/main.cc
index 1100443..486fbda 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -33,6 +33,9 @@
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_mixer.h>
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
 #include "config.h"
 #include "preference.h"
 #include "game.h"
@@ -82,6 +85,15 @@ void InitPref()
     Utils::LoadPref();
 }
 
+#ifdef __EMSCRIPTEN__
+// Called by the page when the tab is hidden or closed: the game only writes its preferences (options,
+// unlocked levels, high scores) on exit.
+extern "C" EMSCRIPTEN_KEEPALIVE void fredygames_save()
+{
+    Utils::SauvePref();
+}
+#endif
+
 /*** Preogramme principale ***/
 /*****************************/
 int main(int narg, char *argv[])
@@ -108,6 +120,10 @@ int main(int narg, char *argv[])
 
     // Demande la resolution Video
     int vOption = SDL_WINDOW_RESIZABLE;
+#ifdef __EMSCRIPTEN__
+    vOption = 0;
+    Pref.FullScreen = false;
+#endif
     if (Pref.FullScreen) {
         vOption |= SDL_WINDOW_FULLSCREEN_DESKTOP;
     }
diff --git a/src/menu.cc b/src/menu.cc
index 6432693..9cee206 100644
--- a/src/menu.cc
+++ b/src/menu.cc
@@ -28,6 +28,9 @@
 #include <SDL2/SDL_audio.h> // for SDL_MIX_MAXVOLUME
 #include <SDL2/SDL_events.h> // for SDL_PollEvent, SDL_Event, SDL_KEYDOWN
 #include <SDL2/SDL_keyboard.h> // for SDL_StopTextInput, SDL_StartTextInput
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
 #include <SDL2/SDL_keycode.h> // for SDLK_F12, SDLK_RETURN, SDLK_ESCAPE
 #include <SDL2/SDL_mouse.h> // for SDL_ShowCursor
 #include <SDL2/SDL_rect.h> // for SDL_Rect
@@ -73,6 +76,11 @@ void Sleeping()
         SDL_Delay(delay);
         Horloge = SDL_GetTicks();
     }
+#ifdef __EMSCRIPTEN__
+    else {
+        emscripten_sleep(0);
+    }
+#endif
 }
 
 /*** Ajoute une entrée dans le tableau des boutons ***/
@@ -93,6 +101,11 @@ void AddBouton(int Num, e_Sprite NumSp, int X, int Y)
 /***********************/
 void ChangeVideo()
 {
+#ifdef __EMSCRIPTEN__
+    // The page has its own fullscreen button.
+    Pref.FullScreen = false;
+    return;
+#endif
     Uint32 flag = SDL_WINDOW_RESIZABLE;
     if (Pref.FullScreen) {
         flag = SDL_WINDOW_FULLSCREEN_DESKTOP;
diff --git a/src/sprite.cc b/src/sprite.cc
index ea3b243..edacd05 100644
--- a/src/sprite.cc
+++ b/src/sprite.cc
@@ -30,6 +30,21 @@
 #include "preference.h"
 #include "utils.h"
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+// Downloads lang/<name>.gz next to the page, decompresses it and writes /<name>.
+EM_ASYNC_JS(void, fredygames_fetch, (const char *name), {
+    const file = UTF8ToString(name);
+    try {
+        const response = await fetch('lang/' + file + '.gz');
+        if (!response.ok) return;
+        const data = await new Response(response.body.pipeThrough(new DecompressionStream('gzip'))).arrayBuffer();
+        FS.writeFile('/' + file, new Uint8Array(data));
+    } catch (e) {
+    }
+});
+#endif
+
 /*** Variables Globales ***/
 /**************************/
 extern SDL_Renderer *sdlRenderer;
@@ -79,6 +94,11 @@ bool LoadLangue()
     char PathFile[512];
 
     strcpy(PathFile, Langue[Pref.Langue]);
+#ifdef __EMSCRIPTEN__
+    if (Utils::FileExists(PathFile) == false) {
+        fredygames_fetch(PathFile);
+    }
+#endif
     Utils::GetPath(PathFile);
     if (Utils::FileExists(PathFile) == false) {
         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Unable to find '%s'", Langue[Pref.Langue]);