diff --git a/src/game.cpp b/src/game.cpp
index e506164..3164685 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -2088,6 +2088,9 @@ auto game::advance_time_action_tick() -> int
 // Returns true if game is over (death, saved, quit, etc)
 bool game::do_turn()
 {
+#if defined(__EMSCRIPTEN__)
+    EM_ASM( window.game_unsaved = true; window.bnSaveRevision = ( window.bnSaveRevision || 0 ) + 1; );
+#endif
     ZoneScopedN( "game::do_turn" );
     const auto reset_time_action_tick = on_out_of_scope( [this]() {
         action_time_scale::set_calendar_turns_this_tick_to_next_tick(
@@ -4488,6 +4491,9 @@ bool game::save( bool quitting )
 
             auto duration = world->commit_save_tx();
             add_msg( m_info, _( "World Saved (took %dms)." ), duration );
+#if defined(__EMSCRIPTEN__)
+            EM_ASM( window.bnPersist?.(); );
+#endif
             return true;
         }
     } catch( std::ios::failure &err ) {
diff --git a/src/ncurses_def.cpp b/src/ncurses_def.cpp
index 3bfb91b..a4d967b 100644
--- a/src/ncurses_def.cpp
+++ b/src/ncurses_def.cpp
@@ -29,6 +29,57 @@
 
 #include "ncurses_def.h"
 
+#if defined(__EMSCRIPTEN__)
+#include <emscripten.h>
+
+// Suspend only the WebAssembly call stack while waiting for browser input.
+// ncurses still handles all window composition and terminal output.
+EM_ASYNC_JS( int, browser_getch, ( int delay ), {
+    window.bnFlushOutput?.();
+    if( window.bnInput.length ) { return window.bnInput.shift(); }
+    if( delay === 0 ) { return -1; }
+    await new Promise( resolve => {
+        let timer;
+        const finish = () => {
+            clearTimeout( timer );
+            window.bnInputWaiter = null;
+            resolve();
+        };
+        window.bnInputWaiter = finish;
+        if( delay > 0 ) { timer = setTimeout( finish, delay ); }
+    } );
+    return window.bnInput.shift() ?? -1;
+} );
+
+EM_JS( void, browser_ungetch, ( int key ), {
+    window.bnInput.unshift( key );
+} );
+
+EM_JS( int, browser_rows, (), { return window.bnRows; } );
+EM_JS( int, browser_columns, (), { return window.bnCols; } );
+
+EM_ASYNC_JS( void, browser_present, (), {
+    window.bnFlushOutput?.();
+    if( window.scheduler?.yield ) {
+        await window.scheduler.yield();
+    } else {
+        await new Promise( resolve => setTimeout( resolve, 0 ) );
+    }
+} );
+#endif
+
+namespace
+{
+auto next_utf8_byte() -> int
+{
+#if defined(__EMSCRIPTEN__)
+    return browser_getch( 0 );
+#else
+    return getch();
+#endif
+}
+} // namespace
+
 struct pairs {
     catacurses::base_color FG;
     catacurses::base_color BG;
@@ -161,7 +212,10 @@ void refresh_display()
 
 void catacurses::doupdate()
 {
-    return curses_check_result( ::doupdate(), OK, "doupdate" );
+    curses_check_result( ::doupdate(), OK, "doupdate" );
+#if defined(__EMSCRIPTEN__)
+    browser_present();
+#endif
 }
 
 void catacurses::clear()
@@ -280,6 +334,12 @@ catacurses::window catacurses::stdscr;
 
 void catacurses::resizeterm()
 {
+#if defined(__EMSCRIPTEN__)
+    ::resizeterm( browser_rows(), browser_columns() );
+    game_ui::init_ui();
+    ui_manager::screen_resized();
+    catacurses::doupdate();
+#else
     const int new_x = ::getmaxx( stdscr.get<::WINDOW>() );
     const int new_y = ::getmaxy( stdscr.get<::WINDOW>() );
     if( ::is_term_resized( new_x, new_y ) ) {
@@ -287,6 +347,7 @@ void catacurses::resizeterm()
         ui_manager::screen_resized();
         catacurses::doupdate();
     }
+#endif
 }
 
 // init_interface is defined in another cpp file, depending on build type:
@@ -330,7 +391,11 @@ void input_manager::pump_events()
     const int prev_timeout = input_timeout;
     set_timeout( 0 );
     do {
+#if defined(__EMSCRIPTEN__)
+        key = browser_getch( 0 );
+#else
         key = getch();
+#endif
         if( key == KEY_RESIZE ) {
             resize = true;
         }
@@ -351,19 +416,31 @@ input_event input_manager::get_input_event()
         previously_pressed_key = 0;
         // flush any output
         catacurses::doupdate();
+#if defined(__EMSCRIPTEN__)
+        key = browser_getch( input_timeout );
+#else
         key = getch();
+#endif
         if( key != ERR ) {
             int newch;
             // Clear the buffer of characters that match the one we're going to act on.
             const int prev_timeout = input_timeout;
             set_timeout( 0 );
             do {
+#if defined(__EMSCRIPTEN__)
+                newch = browser_getch( 0 );
+#else
                 newch = getch();
+#endif
             } while( newch != ERR && newch == key );
             set_timeout( prev_timeout );
             // If we read a different character than the one we're going to act on, re-queue it.
             if( newch != ERR && newch != key ) {
+#if defined(__EMSCRIPTEN__)
+                browser_ungetch( newch );
+#else
                 ungetch( newch );
+#endif
             }
         }
         rval = input_event();
@@ -408,14 +485,14 @@ input_event input_manager::get_input_event()
             if( key < 127 ) {
                 // Single byte sequence
             } else if( 194 <= key && key <= 223 ) {
-                rval.text.append( 1, static_cast<char>( getch() ) );
+                rval.text.append( 1, static_cast<char>( next_utf8_byte() ) );
             } else if( 224 <= key && key <= 239 ) {
-                rval.text.append( 1, static_cast<char>( getch() ) );
-                rval.text.append( 1, static_cast<char>( getch() ) );
+                rval.text.append( 1, static_cast<char>( next_utf8_byte() ) );
+                rval.text.append( 1, static_cast<char>( next_utf8_byte() ) );
             } else if( 240 <= key && key <= 244 ) {
-                rval.text.append( 1, static_cast<char>( getch() ) );
-                rval.text.append( 1, static_cast<char>( getch() ) );
-                rval.text.append( 1, static_cast<char>( getch() ) );
+                rval.text.append( 1, static_cast<char>( next_utf8_byte() ) );
+                rval.text.append( 1, static_cast<char>( next_utf8_byte() ) );
+                rval.text.append( 1, static_cast<char>( next_utf8_byte() ) );
             } else {
                 // Other control character, etc. - no text at all, return an event
                 // without the text property
diff --git a/src/options.cpp b/src/options.cpp
index f3ec2b8..5aa3651 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -4413,6 +4413,9 @@ void options_manager::cache_to_globals()
     safe_mode_proximity = ::get_option<int>( "SAFEMODEPROXIMITY" );
 
     parallel_enabled          = ::get_option<bool>( "MULTITHREADING_ENABLED" );
+#if defined(__EMSCRIPTEN__)
+    parallel_enabled = false;
+#endif
     parallel_monster_planning = ::get_option<bool>( "PARALLEL_MONSTER_PLANNING" );
     monster_plan_chunk_size   = ::get_option<int>( "MONSTER_PLAN_CHUNK_SIZE" );
     parallel_map_cache        = ::get_option<bool>( "PARALLEL_MAP_CACHE" );
diff --git a/src/thread_pool.cpp b/src/thread_pool.cpp
index 2d522da..6b2b26c 100644
--- a/src/thread_pool.cpp
+++ b/src/thread_pool.cpp
@@ -83,6 +83,11 @@ void cata_thread_pool::submit( std::function<void()> task )
 
 cata_thread_pool &get_thread_pool()
 {
+#if defined(__EMSCRIPTEN__)
+    // Browser builds run the existing synchronous fallback on one thread.
+    static auto pool = cata_thread_pool( 0 );
+    return pool;
+#else
     // Worker count is read once at first call (the static pool is constructed
     // only once).  Changes to THREAD_POOL_WORKERS or MULTITHREADING_ENABLED
     // require a restart.
@@ -104,4 +109,5 @@ cata_thread_pool &get_thread_pool()
         return hc > 1u ? hc - 1u : 0u;
     }() );
     return pool;
+#endif
 }
diff --git a/src/utils/url.cpp b/src/utils/url.cpp
index 09082f6..13b3d44 100644
--- a/src/utils/url.cpp
+++ b/src/utils/url.cpp
@@ -9,6 +9,14 @@
 #include <string>
 
 auto open_url(const std::string& url) -> void {
+#if defined(__EMSCRIPTEN__)
+    EM_ASM({
+        const url = new URL( UTF8ToString( $0 ) );
+        if( url.protocol === 'https:' || url.protocol === 'http:' ) {
+            window.open( url.href, '_blank', 'noopener,noreferrer' );
+        }
+    }, url.c_str() );
+#else
     static const auto executable =
 #if defined(_WIN32)
         "start \"\"";
@@ -25,6 +33,7 @@ auto open_url(const std::string& url) -> void {
     if (exitcode != 0) {
         debugmsg("Failed to open URL: %s\nAttemped command was: %s", url, command);
     }
+#endif
 }
 
 auto encode_url(const std::string& text) -> std::string {