diff --git a/Makefile b/Makefile
index c167162bc5..ac47639628 100644
--- a/Makefile
+++ b/Makefile
@@ -104,6 +104,23 @@ ARCH=$(COMPILE_ARCH)
 endif
 export ARCH
 
+ifeq ($(findstring /emcc,$(CC)),/emcc)
+  PLATFORM=emscripten
+  ARCH=wasm32
+  BINEXT=.js
+  # Dynamic linking is not supported.
+  USE_RENDERER_DLOPEN=0
+  USE_OPENAL_DLOPEN=0
+  BUILD_GAME_SO=0
+  USE_CURL=0
+  # Would be interesting to try to get the server working via WebRTC data channel (uses UDP).
+  BUILD_SERVER=0
+  # gl4es translates GL 1.1 to ES 2, and Emscripten translates from ES 2 to WebGL.
+  USE_GL4ES=1
+  # In theory gl4es supports GL 2.1, but in practice not really.
+  BUILD_RENDERER_OPENGL2=0
+endif
+
 ifneq ($(PLATFORM),$(COMPILE_PLATFORM))
   CROSS_COMPILING=1
 else
@@ -207,6 +224,10 @@ ifndef USE_FREETYPE
 USE_FREETYPE=0
 endif
 
+ifndef USE_GL4ES
+USE_GL4ES=0
+endif
+
 ifndef USE_INTERNAL_LIBS
 USE_INTERNAL_LIBS=1
 endif
@@ -231,6 +252,10 @@ ifndef USE_INTERNAL_JPEG
 USE_INTERNAL_JPEG=$(USE_INTERNAL_LIBS)
 endif
 
+ifndef USE_INTERNAL_GL4ES
+USE_INTERNAL_GL4ES=$(USE_INTERNAL_LIBS)
+endif
+
 ifndef USE_LOCAL_HEADERS
 USE_LOCAL_HEADERS=$(USE_INTERNAL_LIBS)
 endif
@@ -275,6 +300,7 @@ OGGDIR=$(MOUNT_DIR)/libogg-1.3.3
 VORBISDIR=$(MOUNT_DIR)/libvorbis-1.3.6
 OPUSDIR=$(MOUNT_DIR)/opus-1.2.1
 OPUSFILEDIR=$(MOUNT_DIR)/opusfile-0.9
+GL4ESDIR=$(MOUNT_DIR)/gl4es
 ZDIR=$(MOUNT_DIR)/zlib
 TOOLSDIR=$(MOUNT_DIR)/tools
 Q3ASMDIR=$(MOUNT_DIR)/tools/asm
@@ -714,7 +740,9 @@ ifdef MINGW
   SHLIBCFLAGS=
   SHLIBLDFLAGS=-shared $(LDFLAGS)
 
-  BINEXT=.exe
+  ifndef BINEXT
+    BINEXT=.exe
+  endif
 
   ifeq ($(CROSS_COMPILING),0)
     TOOLS_BINEXT=.exe
@@ -1063,6 +1091,34 @@ endif #NetBSD
 endif #IRIX
 endif #SunOS
 
+#############################################################################
+# SETUP AND BUILD -- EMSCRIPTEN
+#############################################################################
+ifeq ($(PLATFORM),emscripten)
+  OPTIMIZEVM=-O3
+  OPTIMIZE=$(OPTIMIZEVM) -ffast-math
+  HAVE_VM_COMPILED=false
+  # Some of these warnings may actually be legit problems and should be fixed at some point.
+  BASE_CFLAGS+=-Wno-deprecated-non-prototype -Wno-dangling-else -Wno-implicit-const-int-float-conversion -Wno-misleading-indentation -Wno-format-overflow -Wno-logical-not-parentheses
+  DEBUG_CFLAGS=-g3 -O0 # -fsanitize=address -fsanitize=undefined
+  # Emscripten needs debug flags to be passed to the linker as well
+  DEBUG_LDFLAGS=$(DEBUG_CFLAGS)
+  CLIENT_CFLAGS+=-sUSE_SDL=2
+  CLIENT_LDFLAGS+=\
+    -O3 \
+    -sALLOW_MEMORY_GROWTH \
+    -sEXIT_RUNTIME=1 \
+    -sFULL_ES2=1 \
+    -sSTACK_SIZE=5MB \
+    -sEXPORT_ES6 \
+    -sEXPORT_NAME=ioquake3 \
+    -sUSE_ES6_IMPORT_META \
+    -sEXPORTED_RUNTIME_METHODS=FS,addRunDependency,removeRunDependency
+  BUILD_GAME_SO=0
+  BUILD_GAME_QVM=0
+endif
+
+
 ifndef CC
   CC=gcc
 endif
@@ -1157,6 +1213,14 @@ ifeq ($(USE_CURL),1)
   endif
 endif
 
+ifeq ($(USE_GL4ES),1)
+  CLIENT_CFLAGS += -DUSE_GL4ES
+endif
+
+ifeq ($(USE_INTERNAL_GL4ES),1)
+  BASE_CFLAGS += -I$(GL4ESDIR)/include -DNOEGL -DNOX11 -DEGL_NO_X11 -DNO_GBM
+endif
+
 ifeq ($(USE_VOIP),1)
   CLIENT_CFLAGS += -DUSE_VOIP
   SERVER_CFLAGS += -DUSE_VOIP
@@ -1408,7 +1472,8 @@ all: debug release
 debug:
 	@$(MAKE) targets B=$(BD) CFLAGS="$(CFLAGS) $(BASE_CFLAGS) $(DEPEND_CFLAGS)" \
 	  OPTIMIZE="$(DEBUG_CFLAGS)" OPTIMIZEVM="$(DEBUG_CFLAGS)" \
-	  CLIENT_CFLAGS="$(CLIENT_CFLAGS)" SERVER_CFLAGS="$(SERVER_CFLAGS)" V=$(V)
+	  CLIENT_CFLAGS="$(CLIENT_CFLAGS)" SERVER_CFLAGS="$(SERVER_CFLAGS)" V=$(V) \
+	  LDFLAGS="$(LDFLAGS) $(DEBUG_LDFLAGS)"
 
 release:
 	@$(MAKE) targets B=$(BR) CFLAGS="$(CFLAGS) $(BASE_CFLAGS) $(DEPEND_CFLAGS)" \
@@ -1525,6 +1590,7 @@ makedirs:
 	@$(MKDIR) $(B)/autoupdater
 	@$(MKDIR) $(B)/client/opus
 	@$(MKDIR) $(B)/client/vorbis
+	@$(MKDIR) $(B)/client/gl4es
 	@$(MKDIR) $(B)/renderergl1
 	@$(MKDIR) $(B)/renderergl2
 	@$(MKDIR) $(B)/renderergl2/glsl
@@ -1873,10 +1939,15 @@ Q3OBJ = \
 ifdef MINGW
   Q3OBJ += \
     $(B)/client/con_passive.o
+else
+ifeq ($(PLATFORM),emscripten)
+  Q3OBJ += \
+    $(B)/client/con_passive.o
 else
   Q3OBJ += \
     $(B)/client/con_tty.o
 endif
+endif
 
 Q3R2OBJ = \
   $(B)/renderergl2/tr_animation.o \
@@ -2062,6 +2133,83 @@ ifeq ($(ARCH),x86_64)
     $(B)/client/ftola.o
 endif
 
+ifeq ($(USE_INTERNAL_GL4ES),1)
+  # Don't build this file, it has too many local variables and causes the emscripten build to throw an error on load.
+  # We don't need this functionality so we compile a non-functioning stub version instead, arbgenerator_stubs.c
+  #  $(B)/client/gl4es/arbgenerator.o
+
+  Q3OBJ += \
+    $(B)/client/gl4es/arbgenerator_stubs.o \
+    $(B)/client/gl4es/hardext.o \
+    $(B)/client/gl4es/texture_compressed.o \
+    $(B)/client/gl4es/envvars.o \
+    $(B)/client/gl4es/string_utils.o \
+    $(B)/client/gl4es/matheval.o \
+    $(B)/client/gl4es/texture_read.o \
+    $(B)/client/gl4es/depth.o \
+    $(B)/client/gl4es/vertexattrib.o \
+    $(B)/client/gl4es/decompress.o \
+    $(B)/client/gl4es/uniform.o \
+    $(B)/client/gl4es/raster.o \
+    $(B)/client/gl4es/queries.o \
+    $(B)/client/gl4es/gl_lookup.o \
+    $(B)/client/gl4es/matvec.o \
+    $(B)/client/gl4es/matrix.o \
+    $(B)/client/gl4es/listrl.o \
+    $(B)/client/gl4es/texture_params.o \
+    $(B)/client/gl4es/glstate.o \
+    $(B)/client/gl4es/enable.o \
+    $(B)/client/gl4es/texture_3d.o \
+    $(B)/client/gl4es/pixel.o \
+    $(B)/client/gl4es/shaderconv.o \
+    $(B)/client/gl4es/framebuffers.o \
+    $(B)/client/gl4es/logs.o \
+    $(B)/client/gl4es/drawing.o \
+    $(B)/client/gl4es/list.o \
+    $(B)/client/gl4es/arbhelper.o \
+    $(B)/client/gl4es/pointsprite.o \
+    $(B)/client/gl4es/debug.o \
+    $(B)/client/gl4es/arbconverter.o \
+    $(B)/client/gl4es/texenv.o \
+    $(B)/client/gl4es/eval.o \
+    $(B)/client/gl4es/init.o \
+    $(B)/client/gl4es/gl4es.o \
+    $(B)/client/gl4es/program.o \
+    $(B)/client/gl4es/shader_hacks.o \
+    $(B)/client/gl4es/fpe_cache.o \
+    $(B)/client/gl4es/getter.o \
+    $(B)/client/gl4es/line.o \
+    $(B)/client/gl4es/hint.o \
+    $(B)/client/gl4es/samplers.o \
+    $(B)/client/gl4es/fpe.o \
+    $(B)/client/gl4es/directstate.o \
+    $(B)/client/gl4es/listdraw.o \
+    $(B)/client/gl4es/face.o \
+    $(B)/client/gl4es/array.o \
+    $(B)/client/gl4es/preproc.o \
+    $(B)/client/gl4es/blit.o \
+    $(B)/client/gl4es/stack.o \
+    $(B)/client/gl4es/fog.o \
+    $(B)/client/gl4es/gles.o \
+    $(B)/client/gl4es/glstub.o \
+    $(B)/client/gl4es/gl4eswraps.o \
+    $(B)/client/gl4es/stubs.o \
+    $(B)/client/gl4es/render.o \
+    $(B)/client/gl4es/texture.o \
+    $(B)/client/gl4es/light.o \
+    $(B)/client/gl4es/build_info.o \
+    $(B)/client/gl4es/loader.o \
+    $(B)/client/gl4es/fpe_shader.o \
+    $(B)/client/gl4es/shader.o \
+    $(B)/client/gl4es/texgen.o \
+    $(B)/client/gl4es/planes.o \
+    $(B)/client/gl4es/arbparser.o \
+    $(B)/client/gl4es/oldprogram.o \
+    $(B)/client/gl4es/buffers.o \
+    $(B)/client/gl4es/stencil.o \
+    $(B)/client/gl4es/blend.o
+endif
+
 ifeq ($(NEED_OPUS),1)
 ifeq ($(USE_INTERNAL_OPUS),1)
 Q3OBJ += \
@@ -2802,6 +2950,18 @@ $(B)/client/opus/%.o: $(OPUSDIR)/silk/float/%.c
 $(B)/client/%.o: $(OPUSFILEDIR)/src/%.c
 	$(DO_CC)
 
+$(B)/client/gl4es/%.o: $(GL4ESDIR)/src/gl/%.c
+	$(DO_CC)
+
+$(B)/client/gl4es/%.o: $(GL4ESDIR)/src/gl/math/%.c
+	$(DO_CC)
+
+$(B)/client/gl4es/%.o: $(GL4ESDIR)/src/gl/wrap/%.c
+	$(DO_CC)
+
+$(B)/client/gl4es/%.o: $(GL4ESDIR)/src/glx/%.c
+	$(DO_CC)
+
 $(B)/client/%.o: $(ZDIR)/%.c
 	$(DO_CC)
 
diff --git a/README.md b/README.md
index ce2999cba1..2ff5ad07fe 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,7 @@ Some of the major features currently implemented are:
   * Multiuser support on Windows systems (user specific game data
     is stored in "%APPDATA%\Quake3")
   * PNG support
+  * Web support via Emscripten and GL4ES
   * Many, many bug fixes
 
 The map editor and associated compiling tools are not included. We suggest you
@@ -98,6 +99,22 @@ For macOS, building a Universal Binary 2 (macOS 10.9+, arm64, x86_64)
   4. Copy the resulting ioquake3.app in /build/release-darwin-universal2
      to your /Applications/ioquake3 folder.
 
+For Web, building with Emscripten
+  1. Follow the installation instructions for the Emscripten SDK including
+     setting up the environment with emsdk_env.
+  2. Run `emmake make debug` (or release, but if you do both then you will
+     need to pass an extra URL parameter to the HTML file to select the
+     build you want).
+  3. Start a web server that serves this directory and also a directory
+     containing your game data files (baseq3, missionpack, etc).
+     `python3 -m http.server` is an easy default that you may already have
+     installed.
+  4. Open code/web/ioquake3.html?pakPathname=/path/to/your/baseq3 in a web
+     browser. Open the developer console to see errors and warnings.
+  5. Debugging the C code is possible using a Chrome extension. For details
+     see https://developer.chrome.com/blog/wasm-debugging-2020
+
+
 Installation, for *nix
   1. Set the COPYDIR variable in the shell to be where you installed Quake 3
      to. By default it will be /usr/local/games/quake3 if you haven't set it.
@@ -151,6 +168,7 @@ Makefile.local:
   USE_INTERNAL_OGG     - build and link against internal ogg library
   USE_INTERNAL_OPUS    - build and link against internal opus/opusfile libraries
   USE_INTERNAL_VORBIS  - build and link against internal Vorbis library
+  USE_INTERNAL_GL4ES   - build and link against internal GL4ES library
   USE_LOCAL_HEADERS    - use headers local to ioq3 instead of system ones
   DEBUG_CFLAGS         - C compiler flags to use for building debug version
   COPYDIR              - the target installation directory
diff --git a/code/qcommon/q_platform.h b/code/qcommon/q_platform.h
index 72dbfe1de1..44ece0a157 100644
--- a/code/qcommon/q_platform.h
+++ b/code/qcommon/q_platform.h
@@ -304,6 +304,19 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 #endif
 
+//============================================================ EMSCRIPTEN ===
+
+#if defined(__EMSCRIPTEN__)
+#define OS_STRING "emscripten"
+#define ARCH_STRING "wasm32"
+#define ID_INLINE inline
+#define PATH_SEP '/'
+
+#define Q3_LITTLE_ENDIAN
+
+#define DLL_EXT ".wasm"
+#endif
+
 //===========================================================================
 
 //catch missing defines in above blocks
diff --git a/code/renderergl2/tr_extensions.c b/code/renderergl2/tr_extensions.c
index ebc985a9e4..1f4175eac5 100644
--- a/code/renderergl2/tr_extensions.c
+++ b/code/renderergl2/tr_extensions.c
@@ -27,6 +27,13 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #	include <SDL.h>
 #endif
 
+#ifdef USE_GL4ES
+#include <gl4esinit.h>
+#define ioq3_GetProcAddress gl4es_GetProcAddress
+#else
+#define ioq3_GetProcAddress SDL_GL_GetProcAddress
+#endif
+
 #include "tr_local.h"
 #include "tr_dsa.h"
 
@@ -51,7 +58,7 @@ void GLimp_InitExtraExtensions(void)
 #undef GLE
 
 	// GL function loader, based on https://gist.github.com/rygorous/16796a0c876cf8a5f542caddb55bce8a
-#define GLE(ret, name, ...) qgl##name = (name##proc *) SDL_GL_GetProcAddress("gl" #name);
+#define GLE(ret, name, ...) qgl##name = (name##proc *) ioq3_GetProcAddress("gl" #name);
 
 	// OpenGL 1.5 - GL_ARB_occlusion_query
 	glRefConfig.occlusionQuery = qtrue;
diff --git a/code/sdl/sdl_glimp.c b/code/sdl/sdl_glimp.c
index 30986ab118..8a9b360f0a 100644
--- a/code/sdl/sdl_glimp.c
+++ b/code/sdl/sdl_glimp.c
@@ -35,6 +35,14 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #include "../sys/sys_local.h"
 #include "sdl_icon.h"
 
+#ifdef USE_GL4ES
+#include <gl4esinit.h>
+#define ioq3_GetProcAddress gl4es_GetProcAddress
+#else
+#define ioq3_GetProcAddress SDL_GL_GetProcAddress
+#endif
+
+
 typedef enum
 {
 	RSERR_OK,
@@ -244,7 +252,7 @@ static qboolean GLimp_GetProcAddresses( qboolean fixedFunction ) {
 #ifdef __SDL_NOGETPROCADDR__
 #define GLE( ret, name, ... ) qgl##name = gl#name;
 #else
-#define GLE( ret, name, ... ) qgl##name = (name##proc *) SDL_GL_GetProcAddress("gl" #name); \
+#define GLE( ret, name, ... ) qgl##name = (name##proc *) ioq3_GetProcAddress("gl" #name); \
 	if ( qgl##name == NULL ) { \
 		ri.Printf( PRINT_ALL, "ERROR: Missing OpenGL function %s\n", "gl" #name ); \
 		success = qfalse; \
@@ -382,6 +390,10 @@ static int GLimp_SetMode(int mode, qboolean fullscreen, qboolean noborder, qbool
 
 	ri.Printf( PRINT_ALL, "Initializing OpenGL display\n");
 
+#if defined(USE_GL4ES)
+	initialize_gl4es();
+#endif
+
 	if ( r_allowResize->integer )
 		flags |= SDL_WINDOW_RESIZABLE;
 
@@ -885,9 +897,9 @@ static void GLimp_InitExtensions( qboolean fixedFunction )
 		{
 			if ( r_ext_multitexture->value )
 			{
-				qglMultiTexCoord2fARB = SDL_GL_GetProcAddress( "glMultiTexCoord2fARB" );
-				qglActiveTextureARB = SDL_GL_GetProcAddress( "glActiveTextureARB" );
-				qglClientActiveTextureARB = SDL_GL_GetProcAddress( "glClientActiveTextureARB" );
+				qglMultiTexCoord2fARB = ioq3_GetProcAddress( "glMultiTexCoord2fARB" );
+				qglActiveTextureARB = ioq3_GetProcAddress( "glActiveTextureARB" );
+				qglClientActiveTextureARB = ioq3_GetProcAddress( "glClientActiveTextureARB" );
 
 				if ( qglActiveTextureARB )
 				{
@@ -923,8 +935,8 @@ static void GLimp_InitExtensions( qboolean fixedFunction )
 			if ( r_ext_compiled_vertex_array->value )
 			{
 				ri.Printf( PRINT_ALL, "...using GL_EXT_compiled_vertex_array\n" );
-				qglLockArraysEXT = ( void ( APIENTRY * )( GLint, GLint ) ) SDL_GL_GetProcAddress( "glLockArraysEXT" );
-				qglUnlockArraysEXT = ( void ( APIENTRY * )( void ) ) SDL_GL_GetProcAddress( "glUnlockArraysEXT" );
+				qglLockArraysEXT = ( void ( APIENTRY * )( GLint, GLint ) ) ioq3_GetProcAddress( "glLockArraysEXT" );
+				qglUnlockArraysEXT = ( void ( APIENTRY * )( void ) ) ioq3_GetProcAddress( "glUnlockArraysEXT" );
 				if (!qglLockArraysEXT || !qglUnlockArraysEXT)
 				{
 					ri.Error (ERR_FATAL, "bad getprocaddress");
diff --git a/code/sys/sys_main.c b/code/sys/sys_main.c
index 0113920b61..08d711292e 100644
--- a/code/sys/sys_main.c
+++ b/code/sys/sys_main.c
@@ -47,6 +47,10 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #include "../qcommon/q_shared.h"
 #include "../qcommon/qcommon.h"
 
+#ifdef __EMSCRIPTEN__
+#	include <emscripten.h>
+#endif
+
 static char binaryPath[ MAX_OSPATH ] = { 0 };
 static char installPath[ MAX_OSPATH ] = { 0 };
 
@@ -863,10 +867,14 @@ int main( int argc, char **argv )
 	signal( SIGTERM, Sys_SigHandler );
 	signal( SIGINT, Sys_SigHandler );
 
+#ifdef __EMSCRIPTEN__
+	emscripten_set_main_loop(Com_Frame, 0, 1);
+#else
 	while( 1 )
 	{
 		Com_Frame( );
 	}
+#endif
 
 	return 0;
 }
diff --git a/code/web/ioquake3.html b/code/web/ioquake3.html
new file mode 100644
index 0000000000..f0dfa89c70
--- /dev/null
+++ b/code/web/ioquake3.html
@@ -0,0 +1,71 @@
+<!DOCTYPE html><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1">
+<title>ioquake3 Emscripten demo</title>
+<style>
+html, body { margin: 0; padding: 0; width: 100%; height: 100%; overflow: hidden; background: rgb(0, 0, 0); display:flex; align-items: center; justify-content: center; }
+canvas { max-width: 100%; max-height: 100%; min-width: 100%; min-height: 100%; object-fit: contain; }
+</style>
+
+<canvas id=canvas></canvas>
+
+<script type=module>
+if (window.location.protocol === 'file:') throw new Error('Unfortunately browser security restrictions prevent loading wasm from a file: URL. This file must be loaded from a web server. The easiest way to do this is probably to use Python\'s built-in web server by running `python3 -m http.server` in the top level ioq3 directory and then navigating to http://localhost:8000/code/web/ioquake3.html in your web browser. Note that you will also need to serve the game asset files, either on the same server or a different one.');
+
+// First set up the command line arguments and the Emscripten filesystem.
+const urlParams = new URLSearchParams(window.location.search);
+let pakPathname = urlParams.get('pakPathname');
+if (!pakPathname) throw new Error('\n\nYou need to specify a pakPathname query parameter in the URL. This needs to be a relative or absolute URL to a directory (e.g. ./baseq3 or https://foo.com/bar/baseq3) on a web server containing asset files (e.g. pak0.pk3). The asset files will be placed in the Emscripten virtual filesystem at ~/.q3a/[your_directory_name], where your_directory_name is the basename of the URL you provided (e.g. baseq3). For convenience, this directory name will also be provided as an argument to the game in the form "+set fs_game [your_directory_name]".\n\nYou should also specify an args URL parameter containing additional command line arguments you want to provide to the game. Be warned however that "+" needs to be encoded as "%2b" in URLs or it will be stripped.\n');
+const pakBasename = pakPathname?.substring(pakPathname.lastIndexOf('/') + 1);
+let generatedArguments = `
+    +set net_enabled 0
+    +set r_mode -2
+`;
+if (pakBasename && pakBasename.indexOf(':') === -1) {
+    generatedArguments += ` +set fs_game ${pakBasename} `;
+} else {
+    pakBasename = 'baseq3';
+}
+// Note that unfortunately "+" needs to be encoded as "%2b" in URL query strings or it will be stripped by the browser.
+let queryArgs = urlParams.get('args');
+if (queryArgs) generatedArguments += ` ${queryArgs} `;
+
+// Start fetching all the asset files.
+// There's no standard way to list files in a directory on the web so we just have to hardcode a list of files that might be there.
+const files = ['q3key', 'q3config.cfg', 'autoexec.cfg'];
+const MAX_PAK_FILES = 8;
+for (let i = MAX_PAK_FILES + 1; i >= 0; i--) files.push(`pak${i}.pk3`);
+const assetResponses = [];
+for (const file of files) assetResponses.push(fetch(`${pakPathname}/${file}`).then(r => r.ok ? r.arrayBuffer() : null));
+
+// If buildPath is not specified, try to find a build in one of a few default paths.
+const buildPath = urlParams.get('buildPath');
+const buildPaths = buildPath ? [buildPath] : ['../../build/debug-emscripten-wasm32/', '../../build/release-emscripten-wasm32/', './'];
+const scriptPaths = buildPaths.map(buildPath => buildPath + 'ioquake3.wasm32.js');
+const scriptResponses = await Promise.all(scriptPaths.map(p => fetch(p, {method: 'HEAD'})));
+const validBuilds = scriptResponses.filter(r => r.ok).length;
+if (validBuilds === 0) throw new Error(`Didn't find any wasm builds. Run \`emmake make debug\` to build one, or use the buildPath query parameter to specify a directory containing ioquake3.wasm32.[js,wasm], e.g. ?buildPath=../../build/debug-emscripten-wasm32/`);
+if (validBuilds > 1) throw new Error(`Found multiple valid builds at the following paths: [${buildPaths.filter((path, i)=>scriptResponses[i].ok)}]. Please specify which one to run by adding a buildPath query parameter to the URL, e.g. ?buildPath=../../build/debug-emscripten-wasm32/`);
+const selectedScript = scriptPaths[scriptResponses.findIndex(r => r.ok)];
+
+const ioquake3 = (await import(selectedScript)).default;
+ioquake3({
+    canvas: canvas,
+    arguments: generatedArguments.trim().split(/\s+/),
+    preRun: [async (module) => {
+        // Add the fetched asset files to the Emscripten virtual filesystem.
+        module.addRunDependency('setup-ioq3-filesystem');
+        const buffers = await Promise.all(assetResponses);
+        if (!buffers[files.indexOf(`pak0.pk3`)])
+            throw new Error(`pak0.pk3 not found at ${pakPathname}/pak0.pk3.`);
+        if (buffers[files.indexOf(`pak${MAX_PAK_FILES+1}.pk3`)])
+            throw new Error(`If you want to load more than ${MAX_PAK_FILES} pak files, you need to modify the code in prerun-setup-filesystem.js.`);
+        module.FS.mkdirTree(`/home/web_user/.q3a/${pakBasename}`);
+        for (let i = files.length - 1; i >= 0; i--) {
+            if (buffers[i]) {
+                console.log(`Writing ${files[i]} to Emscripten virtual filesystem at ~/.q3a/${pakBasename}/${files[i]}`);
+                module.FS.writeFile(`/home/web_user/.q3a/${pakBasename}/${files[i]}`, new Uint8Array(buffers[i]));
+            }
+        }
+        module.removeRunDependency('setup-ioq3-filesystem');
+    }],
+});
+</script>