diff --git a/.gitignore b/.gitignore
index df2ce2a0..61f3451a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -77,6 +77,7 @@
 /massif-*.out
 /ms_print.*
 /dukweb.js
+/dukweb.wasm
 /debugger/jquery-ui-1.11.2.zip
 /debugger/jquery-ui-1.11.2/
 /debugger/node_modules/
diff --git a/Makefile b/Makefile
index 2ef6d41b..a4efae32 100644
--- a/Makefile
+++ b/Makefile
@@ -202,6 +202,7 @@ EMCC = emcc
 #EMCCOPTS = -s TOTAL_MEMORY=2097152 -s TOTAL_STACK=524288 --memory-init-file 0
 EMCCOPTS = -O2 -std=c99 -Wall --memory-init-file 0 -s WASM=0 -s POLYFILL_OLD_MATH_FUNCTIONS
 EMCCOPTS_DUKVM = -O2 -std=c99 -Wall --memory-init-file 0 -DEMSCRIPTEN -s WASM=0
+EMCCOPTS_DUKVM_WASM = -O2 -std=c99 -Wall --memory-init-file 0 -DEMSCRIPTEN -s WASM=1
 EMCCOPTS_DUKWEB_EXPORT = -s EXPORTED_FUNCTIONS='["_main","_dukweb_is_open", "_dukweb_open","_dukweb_close","_dukweb_eval"]' -s 'EXTRA_EXPORTED_RUNTIME_METHODS=["ccall","cwrap"]'
 EMDUKOPTS = -s TOTAL_MEMORY=268435456 -DDUK_CMDLINE_PRINTALERT_SUPPORT
 EMDUKOPTS += -DEMSCRIPTEN  # enable stdin workaround in duk_cmdline.c
@@ -261,7 +262,7 @@ clean:
 	@rm -rf test262-*
 	@rm -rf lua-5.2.3
 	@rm -rf luajs
-	@rm -f dukweb.js
+	@rm -f dukweb.js dukweb.wasm
 	@rm -rf /tmp/dukweb-test/
 	@rm -f massif-*.out
 	@rm -f literal_intern_test
@@ -574,9 +575,10 @@ emduk.js: prep/emduk
 # and providing an eval() facility from both sides.  This is a placeholder now
 # and doesn't do anything useful yet.
 dukweb.js: prep/dukweb
-	$(EMCC) $(EMCCOPTS_DUKVM) $(EMCCOPTS_DUKWEB_EXPORT) --post-js dukweb/dukweb_extra.js \
+	@rm -f dukweb.js dukweb.asm
+	$(EMCC) $(EMCCOPTS_DUKVM_WASM) $(EMCCOPTS_DUKWEB_EXPORT) --post-js dukweb/dukweb_extra.js \
 		-Iprep/dukweb prep/dukweb/duktape.c dukweb/dukweb.c -o dukweb.js
-	@wc dukweb.js
+	@wc dukweb.js dukweb.wasm
 literal_intern_test: prep/nondebug misc/literal_intern_test.c
 	$(CC) -o $@ -std=c99 -O2 -fstrict-aliasing -Wall -Wextra \
 		-Iprep/nondebug prep/nondebug/duktape.c misc/literal_intern_test.c -lm
@@ -660,11 +662,11 @@ configuretest:
 
 # Dukweb.js test.
 .PHONY: dukwebtest
-dukwebtest: dukweb.js jquery-1.11.2.js
+dukwebtest: dukweb.js dukweb.wasm jquery-1.11.2.js
 	@echo "### dukwebtest"
 	@rm -rf /tmp/dukweb-test/
 	mkdir /tmp/dukweb-test/
-	cp dukweb.js jquery-1.11.2.js dukweb/dukweb.html dukweb/dukweb.css /tmp/dukweb-test/
+	cp dukweb.js dukweb.wasm jquery-1.11.2.js dukweb/dukweb.html dukweb/dukweb.css /tmp/dukweb-test/
 	@echo "Now point your browser to: file:///tmp/dukweb-test/dukweb.html"
 
 # Third party tests.
@@ -1010,7 +1012,7 @@ dist-iso: dist-src
 .PHONY: tidy-site
 tidy-site:
 	for i in website/*/*.html; do echo "*** Checking $$i"; tidy -q -e -xml $$i; done
-site: duktape-releases dukweb.js jquery-1.11.2.js lz-string
+site: duktape-releases dukweb.js dukweb.wasm jquery-1.11.2.js lz-string
 	rm -rf site
 	mkdir site
 	-cd duktape-releases/; git pull --rebase  # get binaries up-to-date, but allow errors for offline use
diff --git a/RELEASES.rst b/RELEASES.rst
index 1141b2ba..04053e05 100644
--- a/RELEASES.rst
+++ b/RELEASES.rst
@@ -3597,3 +3597,6 @@ Planned
 
 * Don't treat U+180E as whitespace e.g. for String trim() purposes,
   (ES2016, requires Unicode 8.0.0 or higher) (GH-2236)
+
+* Use wasm for dukweb.js compilation (including duktape.org site),
+  fix async loading of emcc-compiled code in dukweb.html (GH-2244)
diff --git a/dukweb/dukweb.html b/dukweb/dukweb.html
index 8278e382..9bc87e1f 100644
--- a/dukweb/dukweb.html
+++ b/dukweb/dukweb.html
@@ -12,11 +12,11 @@
 
 <div id="content-middle">
 
-<p id="dukweb-intro">Works in Chrome/Chromium/Firefox.  There is much to
-improve in the Duktape/browser bindings and errors are not handled nicely
-yet, so keep your Javascript Console open.  Also note that this page takes
-a few seconds to (re)load.  You can embed code in the Dukweb link as a
-fragment identifier: <a href="http://duktape.org/dukweb.html#print('Hello%20world!')%3B">http://duktape.org/dukweb.html#print('Hello%20world!')%3B</a>.</p>
+<p id="dukweb-intro">Duktape compiled using emcc into JS + wasm (can
+also be compiled into pure JS), should work in Chrome/Chromium/Firefox.
+See Web Console for details and errors.  This page takes a a few seconds
+to (re)load.  You can embed code in the Dukweb link as a fragment identifier:
+<a href="http://duktape.org/dukweb.html#print('Hello%20world!')%3B">http://duktape.org/dukweb.html#print('Hello%20world!')%3B</a>.</p>
 
 <div id="dukweb-input-wrapper">
 <textarea id="dukweb-input">
@@ -117,15 +117,15 @@ $(document).ready(function () {
         alert(e);
     }
 
-    try {
+    Duktape.getInitializedPromise().then(function () {
         dukwebSetup();
-    } catch (e) {
+    }).catch(function (e) {
         $('#dukweb-output')
             .addClass('error')
             .text(
                 'Dukweb.js initialization failed (perhaps your browser is not compatible?):\n\n' +
                 String(e.stack || e) + '\n\n');
-    }
+    });
 });
 
 //]]>
diff --git a/dukweb/dukweb_extra.js b/dukweb/dukweb_extra.js
index 31297fa5..1d362d39 100644
--- a/dukweb/dukweb_extra.js
+++ b/dukweb/dukweb_extra.js
@@ -12,11 +12,15 @@
 
 var Duktape = {};
 
+Duktape.initializedPromise = new Promise(function (resolve, reject) {
+    Duktape.initializedPromiseFuncs = [ resolve, reject ];
+});
+
 /*
  *  Utilities
  */
 
-Duktape.log = function() {};
+Duktape.log = function log() {};
 if (typeof console === 'object' && typeof console.log === 'function') {
     Duktape.log = function() {
         console.log.apply(console, arguments);
@@ -28,16 +32,16 @@ if (typeof console === 'object' && typeof console.log === 'function') {
 }
 Duktape.log('Duktape (dukweb) initializing');
 
-Duktape.logOwnProperties = function() {
+Duktape.logOwnProperties = function logOwnProperties() {
     Duktape.log('Own properties of Duktape:');
     Object.getOwnPropertyNames(Duktape).forEach(function (k) {
         var v = Duktape[k];
         if (typeof v === 'function') { v = '[omitted]'; }
         Duktape.log('    ' + k + ' = (' + typeof Duktape[k] + ') ' + String(v));
     });
-}
+};
 
-Duktape.hexVal = function(x, ndigits) {
+Duktape.hexVal = function hexVal(x, ndigits) {
     var nybbles = '0123456789abcdef';
     var i;
     var res = ''
@@ -48,7 +52,7 @@ Duktape.hexVal = function(x, ndigits) {
     return res;
 };
 
-Duktape.escapeTable = (function() {
+Duktape.escapeTable = (function escapeTableInit() {
     var i, n;
     var res = {};
 
@@ -64,7 +68,7 @@ Duktape.escapeTable = (function() {
 })();
 
 // Probably unnecessary, JSON.stringify() escapes strings nicely.
-Duktape.escapeString = function(x) {
+Duktape.escapeString = function escapeString(x) {
     var res = [];
     var i, n = x.length;
     var c;
@@ -74,14 +78,14 @@ Duktape.escapeString = function(x) {
         res.push(esc[c] || '\\u' + Duktape.hexVal(String.charCodeAt(i)));
     }
     return res.join('');
-}
+};
 
 /*
  *  Duktape.eval: run code inside Duktape, encode output value using JSON.
  */
 
 // XXX: errors should probably be promoted to work better
-Duktape.eval = function(code) {
+Duktape.eval = function eval(code) {
     // Code escape into a Javascript string
     var escapedString = JSON.stringify(String(code));
     //var escapedString = '"' + Duktape.escapeString(code) + '"';
@@ -105,17 +109,22 @@ Duktape.eval = function(code) {
  */
 
 // Expect web page to override this, e.g. to append to some buffer.
-Duktape.printHandler = function(msg) {
+Duktape.printHandler = function printHandler(msg) {
     log(msg);
-}
+};
 
 // Expect web page to override this, e.g. to use browser alert().
-Duktape.alertHandler = function(msg) {
+Duktape.alertHandler = function alertHandler(msg) {
     log(msg);
-}
+};
+
+// Get Promise for Dukweb init completion.
+Duktape.getInitializedPromise = function getInitializedPromise() {
+    return Duktape.initializedPromise;
+};
 
 // Asynchronous init, triggered from C main().
-Duktape.initialize = function initialize() {
+Duktape.initializeRaw = function initializeRaw() {
     console.log('Duktape.initialize() start');
 
     /*
@@ -207,4 +216,15 @@ Duktape.initialize = function initialize() {
     //console.log('=== ' + Duktape.eval('Duktape.enc("jx", { env: Duktape.env, version: Duktape.version })') + ' ===');
 
     console.log('Duktape.initialize() end');
-}
+};
+
+Duktape.initialize = function initialize() {
+    try {
+        Duktape.initializeRaw();
+        Duktape.initializedPromiseFuncs[0](Duktape);
+    } catch (e) {
+        Duktape.initializedPromiseFuncs[1](e);
+    } finally {
+        Duktape.initializedPromiseFuncs[1](new Error('internal error'));
+    }
+};
diff --git a/website/buildsite.py b/website/buildsite.py
index ca1db9d7..59fe9bff 100644
--- a/website/buildsite.py
+++ b/website/buildsite.py
@@ -1167,6 +1167,7 @@ def main():
 
     print 'Copying dukweb.js files'
     for i in [ '../dukweb.js',
+               '../dukweb.wasm',
                '../jquery-1.11.2.js',
                '../dukweb/dukweb.css',
                '../dukweb/dukweb.html' ]: