diff --git a/data/berusky.ini b/data/berusky.ini
index 6629d4e..2fdd892 100644
--- a/data/berusky.ini
+++ b/data/berusky.ini
@@ -11,6 +11,10 @@ graphics_data = /usr/share/berusky/Graphics
 fullscreen = 0
 color_depth = 32
 
+# Start in the high resolution mode (1280x960) without asking; the page scales the picture
+# to the player. Added for the browser build of fredygames.com.
+startup_doublesize_question = 0
+
 # Logging
 log = 0
 logfile = ~/.berusky/b1logfile.txt
diff --git a/src/berusky_gui.cpp b/src/berusky_gui.cpp
index c832b3b..0f6d40f 100644
--- a/src/berusky_gui.cpp
+++ b/src/berusky_gui.cpp
@@ -61,9 +61,26 @@ spr_handle menu_background_get(void)
 // Game UI
 // -------------------------------------------------------
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+
+/* The game writes the last used profile only when it quits; the page calls this when the tab is
+ * hidden or closed (the profile progress itself is written after each finished level). */
+static game_gui *fredygames_gui = NULL;
+
+extern "C" EMSCRIPTEN_KEEPALIVE void fredygames_save(void)
+{
+  if(fredygames_gui)
+    fredygames_gui->player_profile_save();
+}
+#endif
+
 game_gui::game_gui(ITEM_REPOSITORY *p_repo_, DIR_LIST *p_dir_)
 : gui_base(), p_repo(p_repo_), p_dir(p_dir_)
 {
+#ifdef __EMSCRIPTEN__
+  fredygames_gui = this;
+#endif
   // Create game main class
   p_ber = new BERUSKY(p_repo_,p_dir);
 
@@ -76,6 +93,9 @@ game_gui::game_gui(ITEM_REPOSITORY *p_repo_, DIR_LIST *p_dir_)
 
 game_gui::~game_gui(void)
 {
+#ifdef __EMSCRIPTEN__
+  fredygames_gui = NULL;
+#endif
   player_profile_save();
 
   if(p_ber)
@@ -271,7 +291,10 @@ void game_gui::menu_main(MENU_STATE state, size_ptr data, size_ptr data1)
         menu_item_draw(profiles, MENU_LEFT, MENU_SAVE_BACK, LEVEL_EVENT(GC_MENU_PROFILES));
         menu_item_draw(settings, MENU_LEFT, MENU_SAVE_BACK, LEVEL_EVENT(GC_MENU_SETTINGS));
         menu_item_draw(help, MENU_LEFT, MENU_SAVE_BACK, LEVEL_EVENT(GC_MENU_HELP,FALSE));
+#ifndef __EMSCRIPTEN__
+        /* The level editor runs as a separate program; there is none in the browser. */
         menu_item_draw(editor, MENU_LEFT, MENU_SAVE_BACK, LEVEL_EVENT(GC_RUN_EDITOR));      
+#endif
         menu_item_draw(quit, MENU_LEFT, MENU_SAVE_BACK, LEVEL_EVENT(GC_MENU_QUIT));
       
         p_font->alignment_set(MENU_CENTER);
diff --git a/src/editor.cpp b/src/editor.cpp
index 04f77ee..9cf11c9 100644
--- a/src/editor.cpp
+++ b/src/editor.cpp
@@ -29,7 +29,9 @@
 #include <stdlib.h>
 #include <time.h>
 #include <string.h>
+#ifndef __EMSCRIPTEN__
 #include <error.h>
+#endif
 #include <errno.h>
 #include <stdio.h>
 
diff --git a/src/input.cpp b/src/input.cpp
index 23c6734..0d8b738 100644
--- a/src/input.cpp
+++ b/src/input.cpp
@@ -157,7 +157,11 @@ bool key_to_ascii(int key, char *p_char)
 bool input::key_status(int sdl_key)
 {
   Uint8 *keystate = SDL_GetKeyState(NULL);
+#ifdef __EMSCRIPTEN__
+  return(keystate[SDL12_KEY(sdl_key)]);
+#else
   return(keystate[sdl_key]);
+#endif
 }
 
 void input::keyset_set(EVENT_KEY_SET *p_keyset)
@@ -260,8 +264,12 @@ void input::key_input(KEYTYPE key, KEYMOD modification, bool pressed)
 
   // Update all key events regard to current keyboard state
   for(i = 0; i < keynum; i++, p_key++) {
+#ifdef __EMSCRIPTEN__
+    if(keystate[SDL12_KEY(p_key->key)] && ctrl == p_key->ctrl && shift == p_key->shift) {
+#else
     assert(p_key->key < numkeys);
     if(keystate[p_key->key] && ctrl == p_key->ctrl && shift == p_key->shift) {
+#endif
       //bprintf("p_key = %p, activated, p_key->key = %d, keystate[p_key->key] = %d",p_key,p_key->key,keystate[p_key->key]);
       p_key->flag = p_key->flag|KEY_PRESSED;
     }
@@ -304,7 +312,8 @@ void input::events_loop(LEVEL_EVENT_QUEUE *p_queue)
           bool pressed = FALSE;
           int  i;
           for(i = 0; i < MOUSE_BUTTONS; i++) {        
-            bool state = event.motion.state&SDL_BUTTON(i);
+            // SDL_BUTTON(0) shifts by -1, which is undefined; clang folds it into "pressed".
+            bool state = i > 0 && (event.motion.state&SDL_BUTTON(i));
             if(state) {
               mouse_input(event.motion.x, event.motion.y, BUTTON_DOWN, i);
               pressed = TRUE;
@@ -321,6 +330,7 @@ void input::events_loop(LEVEL_EVENT_QUEUE *p_queue)
       case SDL_MOUSEBUTTONUP:
         mouse_input(event.button.x, event.button.y, BUTTON_UP, event.button.button);
         break;
+#ifndef __EMSCRIPTEN__
       case SDL_ACTIVEEVENT:
         if(event.active.state&SDL_APPACTIVE) {
           if(event.active.gain) {
@@ -330,6 +340,7 @@ void input::events_loop(LEVEL_EVENT_QUEUE *p_queue)
           }
         }
         break;
+#endif
       case SDL_QUIT:        
         p_queue->add(LEVEL_EVENT(GC_MENU_QUIT));
         p_queue->commit();
@@ -398,7 +409,11 @@ void input::mouse_input(tpos mx, tpos my, MOUSE_BUTTON_STATE state, int button)
       }
     
       if(p_ev->flag&MEVENT_KEY) {
+#ifdef __EMSCRIPTEN__
+        cond_key = p_ev->mstate.key && p_keystate[SDL12_KEY(p_ev->mstate.key)];
+#else
         cond_key = p_ev->mstate.key && p_keystate[p_ev->mstate.key];
+#endif
       }
           
       if(cond_button && cond_key && cond_area) {
diff --git a/src/main.cpp b/src/main.cpp
index 3ea2281..51df268 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -25,7 +25,7 @@
  *
  */
 #include "portability.h"
-#ifdef LINUX
+#if defined(LINUX) && !defined(__EMSCRIPTEN__)
 #include <gtk/gtk.h>
 #endif
 #include <stdio.h>
@@ -285,7 +285,7 @@ int main(int argc, char *argv[])
   setbuf(stderr, NULL);
   srand(clock());
 
-#ifdef LINUX
+#if defined(LINUX) && !defined(__EMSCRIPTEN__)
   gtk_parse_args(&argc, &argv);
 #endif
 
diff --git a/src/utils.cpp b/src/utils.cpp
index b2f1da4..0b0f7d2 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -29,7 +29,9 @@
   Utility
 */
 #include <stdio.h>
+#ifndef __EMSCRIPTEN__
 #include <error.h>
+#endif
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>