diff --git a/src/main_web/emscripten_allocator.odin b/src/main_web/emscripten_allocator.odin
new file mode 100644
index 0000000..bab9a89
--- /dev/null
+++ b/src/main_web/emscripten_allocator.odin
@@ -0,0 +1,126 @@
+/*
+This allocator uses the malloc, calloc, free and realloc procs that emscripten
+exposes in order to allocate memory. Just like Odin's default heap allocator
+this uses proper alignment, so that maps and simd works.
+*/
+
+package main_web
+
+import "core:mem"
+import "core:c"
+import "base:intrinsics"
+
+// This will create bindings to emscripten's implementation of libc
+// memory allocation features.
+@(default_calling_convention = "c")
+foreign {
+	calloc  :: proc(num, size: c.size_t) -> rawptr ---
+	free    :: proc(ptr: rawptr) ---
+	malloc  :: proc(size: c.size_t) -> rawptr ---
+	realloc :: proc(ptr: rawptr, size: c.size_t) -> rawptr ---
+}
+
+emscripten_allocator :: proc "contextless" () -> mem.Allocator {
+	return mem.Allocator{emscripten_allocator_proc, nil}
+}
+
+emscripten_allocator_proc :: proc(
+	allocator_data: rawptr,
+	mode: mem.Allocator_Mode,
+	size, alignment: int,
+	old_memory: rawptr,
+	old_size: int,
+	location := #caller_location
+) -> (data: []byte, err: mem.Allocator_Error)  {
+	// These aligned alloc procs are almost indentical those in
+	// `_heap_allocator_proc` in `core:os`. Without the proper alignment you
+	// cannot use maps and simd features.
+
+	aligned_alloc :: proc(size, alignment: int, zero_memory: bool, old_ptr: rawptr = nil) -> ([]byte, mem.Allocator_Error) {
+		a := max(alignment, align_of(rawptr))
+		space := size + a - 1
+
+		allocated_mem: rawptr
+		if old_ptr != nil {
+			original_old_ptr := mem.ptr_offset((^rawptr)(old_ptr), -1)^
+			allocated_mem = realloc(original_old_ptr, c.size_t(space+size_of(rawptr)))
+		} else if zero_memory {
+			// calloc automatically zeros memory, but it takes a number + size
+			// instead of just size.
+			allocated_mem = calloc(c.size_t(space+size_of(rawptr)), 1)
+		} else {
+			allocated_mem = malloc(c.size_t(space+size_of(rawptr)))
+		}
+		aligned_mem := rawptr(mem.ptr_offset((^u8)(allocated_mem), size_of(rawptr)))
+
+		ptr := uintptr(aligned_mem)
+		aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a)
+		diff := int(aligned_ptr - ptr)
+		if (size + diff) > space || allocated_mem == nil {
+			return nil, .Out_Of_Memory
+		}
+
+		aligned_mem = rawptr(aligned_ptr)
+		mem.ptr_offset((^rawptr)(aligned_mem), -1)^ = allocated_mem
+
+		return mem.byte_slice(aligned_mem, size), nil
+	}
+
+	aligned_free :: proc(p: rawptr) {
+		if p != nil {
+			free(mem.ptr_offset((^rawptr)(p), -1)^)
+		}
+	}
+
+	aligned_resize :: proc(p: rawptr, old_size: int, new_size: int, new_alignment: int) -> ([]byte, mem.Allocator_Error) {
+		if p == nil {
+			return nil, nil
+		}
+		return aligned_alloc(new_size, new_alignment, true, p)
+	}
+
+	switch mode {
+	case .Alloc:
+		return aligned_alloc(size, alignment, true)
+
+	case .Alloc_Non_Zeroed:
+		return aligned_alloc(size, alignment, false)
+
+	case .Free:
+		aligned_free(old_memory)
+		return nil, nil
+
+	case .Resize:
+		if old_memory == nil {
+			return aligned_alloc(size, alignment, true)
+		}
+
+		bytes := aligned_resize(old_memory, old_size, size, alignment) or_return
+
+		// realloc doesn't zero the new bytes, so we do it manually.
+		if size > old_size {
+			new_region := raw_data(bytes[old_size:])
+			intrinsics.mem_zero(new_region, size - old_size)
+		}
+
+		return bytes, nil
+
+	case .Resize_Non_Zeroed:
+		if old_memory == nil {
+			return aligned_alloc(size, alignment, false)
+		}
+
+		return aligned_resize(old_memory, old_size, size, alignment)
+
+	case .Query_Features:
+		set := (^mem.Allocator_Mode_Set)(old_memory)
+		if set != nil {
+			set^ = {.Alloc, .Free, .Resize, .Query_Features}
+		}
+		return nil, nil
+
+	case .Free_All, .Query_Info:
+		return nil, .Mode_Not_Implemented
+	}
+	return nil, .Mode_Not_Implemented
+}
diff --git a/src/main_web/emscripten_logger.odin b/src/main_web/emscripten_logger.odin
new file mode 100644
index 0000000..dddf25e
--- /dev/null
+++ b/src/main_web/emscripten_logger.odin
@@ -0,0 +1,91 @@
+/*
+This logger is largely a copy of the console logger in `core:log`, but it uses
+emscripten's `puts` proc to write into he console of the web browser.
+
+This is more or less identical to the logger in Aronicu's repository:
+https://github.com/Aronicu/Raylib-WASM/tree/main
+*/
+
+package main_web
+
+import "core:c"
+import "core:fmt"
+import "core:log"
+import "core:strings"
+
+Emscripten_Logger_Opts :: log.Options{.Level, .Short_File_Path, .Line}
+
+create_emscripten_logger :: proc (lowest := log.Level.Debug, opt := Emscripten_Logger_Opts) -> log.Logger {
+	return log.Logger{data = nil, procedure = logger_proc, lowest_level = lowest, options = opt}
+}
+
+// This create's a binding to `puts` which will be linked in as part of the
+// emscripten runtime.
+@(default_calling_convention = "c")
+foreign {
+	puts :: proc(buffer: cstring) -> c.int ---
+}
+
+@(private="file")
+logger_proc :: proc(
+	logger_data: rawptr,
+	level: log.Level,
+	text: string,
+	options: log.Options,
+	location := #caller_location
+) {
+	b := strings.builder_make(context.temp_allocator)
+	strings.write_string(&b, Level_Headers[level])
+	do_location_header(options, &b, location)
+	fmt.sbprint(&b, text)
+
+	if bc, bc_err := strings.to_cstring(&b); bc_err == nil {
+		puts(bc)
+	}
+}
+
+@(private="file")
+Level_Headers := [?]string {
+	0 ..< 10 = "[DEBUG] --- ",
+	10 ..< 20 = "[INFO ] --- ",
+	20 ..< 30 = "[WARN ] --- ",
+	30 ..< 40 = "[ERROR] --- ",
+	40 ..< 50 = "[FATAL] --- ",
+}
+
+@(private="file")
+do_location_header :: proc(opts: log.Options, buf: ^strings.Builder, location := #caller_location) {
+	if log.Location_Header_Opts & opts == nil {
+		return
+	}
+	fmt.sbprint(buf, "[")
+	file := location.file_path
+	if .Short_File_Path in opts {
+		last := 0
+		for r, i in location.file_path {
+			if r == '/' {
+				last = i + 1
+			}
+		}
+		file = location.file_path[last:]
+	}
+
+	if log.Location_File_Opts & opts != nil {
+		fmt.sbprint(buf, file)
+	}
+	if .Line in opts {
+		if log.Location_File_Opts & opts != nil {
+			fmt.sbprint(buf, ":")
+		}
+		fmt.sbprint(buf, location.line)
+	}
+
+	if .Procedure in opts {
+		if (log.Location_File_Opts | {.Line}) & opts != nil {
+			fmt.sbprint(buf, ":")
+		}
+		fmt.sbprintf(buf, "%s()", location.procedure)
+	}
+
+	fmt.sbprint(buf, "] ")
+}
diff --git a/src/main_web/index_template.html b/src/main_web/index_template.html
new file mode 100644
index 0000000..39579c5
--- /dev/null
+++ b/src/main_web/index_template.html
@@ -0,0 +1,114 @@
+<!doctype html>
+<html lang="en-us">
+<head>
+	<meta charset="utf-8">
+	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+
+	<title>Odin + Raylib on the web</title>
+	<meta name="title" content="Odin + Raylib on the web">
+	<meta name="description" content="Make games using Odin + Raylib that work in the browser">
+	<meta name="viewport" content="width=device-width">
+
+	<style>
+		body { 
+			margin: 0px; 
+			overflow: hidden; 
+			background-color: black;
+		}
+		canvas.game_canvas { 
+			border: 0px none; 
+			background-color: black;
+			padding-left: 0;
+			padding-right: 0;
+			margin-left: auto;
+			margin-right: auto;
+			display: block;
+		}
+	</style>
+</head>
+<body>
+	<canvas class="game_canvas" id="canvas" oncontextmenu="event.preventDefault()" tabindex="-1" onmousedown="event.target.focus()" onkeydown="event.preventDefault()"></canvas>
+	<script type="text/javascript" src="odin.js"></script>
+	<script>
+		var odinMemoryInterface = new odin.WasmMemoryInterface();
+		odinMemoryInterface.setIntSize(4);
+		var odinImports = odin.setupDefaultImports(odinMemoryInterface);
+
+		// The Module is used as configuration for emscripten.
+		var Module = {
+			// This is called by emscripten when it starts up.
+			instantiateWasm: (imports, successCallback) => {
+				const newImports = {
+					...odinImports,
+					...imports
+				}
+
+				return WebAssembly.instantiateStreaming(fetch("index.wasm"), newImports).then(function(output) {
+					var e = output.instance.exports;
+					odinMemoryInterface.setExports(e);
+					odinMemoryInterface.setMemory(e.memory);
+					return successCallback(output.instance);
+				});
+			},
+			// This happens a bit after `instantiateWasm`, when everything is
+			// done setting up. At that point we can run code.
+			onRuntimeInitialized: () => {
+				var e = wasmExports;
+
+				// Calls any procedure marked with @init
+				e._start();
+
+				// See source/main_web/main_web.odin for main_start,
+				// main_update and main_end.
+				e.main_start();
+
+				function send_resize() {
+					var canvas = document.getElementById('canvas');
+					e.web_window_size_changed(canvas.width, canvas.height);
+				}
+
+				window.addEventListener('resize', function(event) {
+					send_resize();
+				}, true);
+
+				// This can probably be done better: Ideally we'd feed the
+				// initial size to `main_start`. But there seems to be a
+				// race condition. `canvas` doesn't have it's correct size yet.
+				send_resize();
+
+				// Runs the "main loop".
+				function do_main_update() {
+					if (!e.main_update()) {
+						e.main_end();
+
+						// Calls procedures marked with @fini
+						e._end();
+						return;
+					}
+					window.requestAnimationFrame(do_main_update);
+				}
+
+				window.requestAnimationFrame(do_main_update);
+			},
+			print: (function() {
+				var element = document.getElementById("output");
+				if (element) element.value = ''; // clear browser cache
+				return function(text) {
+					if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
+					console.log(text);
+					if (element) {
+					  element.value += text + "\n";
+					  element.scrollTop = element.scrollHeight; // focus on bottom
+					}
+				};
+			})(),
+			canvas: (function() {
+				return document.getElementById("canvas");
+			})()
+		};
+	</script>
+
+	<!-- Emscripten injects its javascript here -->
+	{{{ SCRIPT }}}
+</body>
+</html>
diff --git a/src/main_web/main_web.odin b/src/main_web/main_web.odin
new file mode 100644
index 0000000..047a4aa
--- /dev/null
+++ b/src/main_web/main_web.odin
@@ -0,0 +1,68 @@
+// These procs are the ones that will be called from `index.html`, which is
+// generated from `index_template.html`.
+
+package main_web
+
+import "base:runtime"
+import "core:c"
+import "core:mem"
+
+import emu "../machine"
+import sim "../simulator"
+
+@(private="file")
+web_context: runtime.Context
+
+@export
+main_start :: proc "c" () {
+	context = runtime.default_context()
+
+	// The WASM allocator doesn't seem to work properly in combination with
+	// emscripten. There is some kind of conflict with how the manage memory.
+	// So this sets up an allocator that uses emscripten's malloc.
+	context.allocator = emscripten_allocator()
+	runtime.init_global_temporary_allocator(1*mem.Megabyte)
+
+	// Since we now use js_wasm32 we should be able to remove this and use
+	// context.logger = log.create_console_logger(). However, that one produces
+	// extra newlines on web. So it's a bug in that core lib.
+	context.logger = create_emscripten_logger()
+
+	web_context = context
+
+	// Init the emu 8 "cpu"
+	system := emu.init()
+	s := sim.Simulator {
+		machine = &system,
+		rom_loaded = false,
+		paused = true,
+		step = false,
+		cpu_hz = 700,
+		disasm_follow = true,
+	}
+
+	sim.init(&s)
+}
+
+@export
+main_update :: proc "c" () -> bool {
+	context = web_context
+
+	// TODO
+	sim.update()
+	return sim.should_run()
+}
+
+@export
+main_end :: proc "c" () {
+	context = web_context
+	// TODO
+	sim.shutdown()
+}
+
+@export
+web_window_size_changed :: proc "c" (w: c.int, h: c.int) {
+	context = web_context
+	// TODO
+	game.parent_window_size_changed(int(w), int(h))
+}