diff --git a/test/browser/test_html5_fullscreen.html b/test/browser/test_html5_fullscreen.html
index b26a75e0ab5d6..4702bd52db7e0 100644
--- a/test/browser/test_html5_fullscreen.html
+++ b/test/browser/test_html5_fullscreen.html
@@ -77,8 +77,8 @@
         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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&");
             //text = text.replace(/</g, "&lt;");
@@ -91,13 +91,9 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (function() {
           var canvas = document.getElementById('canvas');
diff --git a/test/browser/test_manual_download_data.html b/test/browser/test_manual_download_data.html
index acb69fc546018..b9511dff8f247 100644
--- a/test/browser/test_manual_download_data.html
+++ b/test/browser/test_manual_download_data.html
@@ -77,8 +77,8 @@
         print: (() => {
           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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -91,13 +91,9 @@
             }
           };
         })(),
-        printErr: (text) => {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (() => {
           var canvas = document.getElementById('canvas');
diff --git a/test/browser/test_preallocated_heap_shell.html b/test/browser/test_preallocated_heap_shell.html
index ae19948017741..7a337209c5f2e 100644
--- a/test/browser/test_preallocated_heap_shell.html
+++ b/test/browser/test_preallocated_heap_shell.html
@@ -79,8 +79,8 @@
         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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -93,13 +93,9 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (function() {
           var canvas = document.getElementById('canvas');
diff --git a/test/browser/test_preinitialized_webgl_context.html b/test/browser/test_preinitialized_webgl_context.html
index e76edb3ee589d..de282972fd6c8 100644
--- a/test/browser/test_preinitialized_webgl_context.html
+++ b/test/browser/test_preinitialized_webgl_context.html
@@ -77,8 +77,8 @@
         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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -91,13 +91,9 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (function() {
           var canvas = document.getElementById('canvas');
diff --git a/test/browser/test_sdl_canvas_size.html b/test/browser/test_sdl_canvas_size.html
index 697259f223eb8..f56b4d5d77e4e 100644
--- a/test/browser/test_sdl_canvas_size.html
+++ b/test/browser/test_sdl_canvas_size.html
@@ -41,8 +41,8 @@
         print: (function() {
           var element = document.getElementById('output');
           element.value = ''; // clear browser cache
-          return function(text) {
-            if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -52,13 +52,9 @@
             element.scrollTop = element.scrollHeight; // focus on bottom
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.log(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: document.getElementById('canvas'),
         setStatus: function(text) {
diff --git a/test/browser/webgl_destroy_context_shell.html b/test/browser/webgl_destroy_context_shell.html
index 9433d358212c8..f815a0d082863 100644
--- a/test/browser/webgl_destroy_context_shell.html
+++ b/test/browser/webgl_destroy_context_shell.html
@@ -77,8 +77,8 @@
         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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -91,13 +91,9 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (function() {
           var canvas = document.getElementById('canvas');
diff --git a/test/canvas_animate_resize_shell.html b/test/canvas_animate_resize_shell.html
index 438fa9cf171a5..0743b08af4805 100644
--- a/test/canvas_animate_resize_shell.html
+++ b/test/canvas_animate_resize_shell.html
@@ -12,16 +12,11 @@
     <textarea class="emscripten" id="output" rows="8" style='width:80%'></textarea>
     <script type='text/javascript'>
       var Module = {
-        print: (function() {
+        print: (() => {
           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(' ');
-            // These replacements are necessary if you render to raw HTML
-            //text = text.replace(/&/g, "&amp;");
-            //text = text.replace(/</g, "&lt;");
-            //text = text.replace(/>/g, "&gt;");
-            //text = text.replace('\n', '<br>', 'g');
+          return (...args) => {
+            var text = args.join(' ');
             console.log(text);
             if (element) {
               element.value += text + "\n";
@@ -29,24 +24,10 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
-        canvas: (function() {
-          var canvas = document.getElementById('canvas');
-
-          // As a default initial behavior, pop up an alert when webgl context is lost. To make your
-          // application robust, you may want to override this behavior before shipping!
-          // See http://www.khronos.org/registry/webgl/specs/latest/1.0/#5.15.2
-          canvas.addEventListener("webglcontextlost", function(e) { alert('WebGL context lost. You will need to reload the page.'); e.preventDefault(); }, false);
-
-          return canvas;
-        })(),
       };
     </script>
     {{{ SCRIPT }}}
diff --git a/test/embind/shell.html b/test/embind/shell.html
index 757d3d17de188..073f7052bea46 100644
--- a/test/embind/shell.html
+++ b/test/embind/shell.html
@@ -38,8 +38,8 @@
         print: (function() {
           var element = document.getElementById('output');
           element.value = ''; // clear browser cache
-          return function(text) {
-            if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -49,13 +49,9 @@
             element.scrollTop = element.scrollHeight; // focus on bottom
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.log(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: document.getElementById('canvas'),
         setStatus: function(text) {
diff --git a/test/pthread/main_js_with_loader.html b/test/pthread/main_js_with_loader.html
index 8f9d30a3acaf6..1cf192eea2d13 100644
--- a/test/pthread/main_js_with_loader.html
+++ b/test/pthread/main_js_with_loader.html
@@ -77,8 +77,8 @@
         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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -91,13 +91,9 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (function() {
           var canvas = document.getElementById('canvas');
diff --git a/test/pthread/test_pthread_mandelbrot_shell.html b/test/pthread/test_pthread_mandelbrot_shell.html
index f5ae7921f9a52..a1b702a9035b3 100644
--- a/test/pthread/test_pthread_mandelbrot_shell.html
+++ b/test/pthread/test_pthread_mandelbrot_shell.html
@@ -1227,8 +1227,8 @@
         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(' ');
+          return (...args) => {
+            var text = args.join(' ');
             // These replacements are necessary if you render to raw HTML
             //text = text.replace(/&/g, "&amp;");
             //text = text.replace(/</g, "&lt;");
@@ -1241,13 +1241,9 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+        printErr(..args) {
+          var text = args.join(' ');
+          console.error(text);
         },
         canvas: (function() {
           var canvas = document.getElementById('canvas');
diff --git a/test/test_fflush.html b/test/test_fflush.html
index 974759d80ad6b..9e5bc25199628 100644
--- a/test/test_fflush.html
+++ b/test/test_fflush.html
@@ -78,20 +78,15 @@
         gotStderr: false,
         gotStdCerr: false,
 
-        reportSuccess: function() {
+        reportSuccess() {
           fetch('/report_result?0').then(() => window.close());
         },
 
-        print: (function() {
+        print: (() => {
           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(' ');
-            // These replacements are necessary if you render to raw HTML
-            //text = text.replace(/&/g, "&amp;");
-            //text = text.replace(/</g, "&lt;");
-            //text = text.replace(/>/g, "&gt;");
-            //text = text.replace('\n', '<br>', 'g');
+          return (...args) {
+            var text = args.join(' ');
             console.log(text);
             if (text == 'hello!') { Module.gotStdout = true; if (Module.gotStderr && Module.gotStdCerr) Module.reportSuccess(); }
             if (element) {
@@ -100,17 +95,13 @@
             }
           };
         })(),
-        printErr: function(text) {
-          if (arguments.length > 1) text = Array.prototype.slice.call(arguments).join(' ');
+        printErr(...args) {
+          var text = args.join(' ');
           if (text == 'hello from stderr too!') { Module.gotStderr = true; if (Module.gotStdout && Module.gotStdCerr) Module.reportSuccess(); }
           if (text == 'std::cerr in two parts.') { Module.gotStdCerr = true; if (Module.gotStdout && Module.gotStderr) Module.reportSuccess(); }
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+          console.error(text);
         },
-        canvas: (function() {
+        canvas() {
           var canvas = document.getElementById('canvas');
 
           // As a default initial behavior, pop up an alert when webgl context is lost. To make your
@@ -119,40 +110,7 @@
           canvas.addEventListener("webglcontextlost", function(e) { alert('WebGL context lost. You will need to reload the page.'); e.preventDefault(); }, false);
 
           return canvas;
-        })(),
-        setStatus: function(text) {
-          if (!Module.setStatus.last) Module.setStatus.last = { time: Date.now(), text: '' };
-          if (text === Module.setStatus.text) return;
-          var m = text.match(/([^(]+)\((\d+(\.\d+)?)\/(\d+)\)/);
-          var now = Date.now();
-          if (m && now - Date.now() < 30) return; // if this is a progress update, skip it if too soon
-          if (m) {
-            text = m[1];
-            progressElement.value = parseInt(m[2])*100;
-            progressElement.max = parseInt(m[4])*100;
-            progressElement.hidden = false;
-            spinnerElement.hidden = false;
-          } else {
-            progressElement.value = null;
-            progressElement.max = null;
-            progressElement.hidden = true;
-            if (!text) spinnerElement.hidden = true;
-          }
-          statusElement.innerHTML = text;
         },
-        totalDependencies: 0,
-        monitorRunDependencies: function(left) {
-          this.totalDependencies = Math.max(this.totalDependencies, left);
-          Module.setStatus(left ? 'Preparing... (' + (this.totalDependencies-left) + '/' + this.totalDependencies + ')' : 'All downloads complete.');
-        }
-      };
-      Module.setStatus('Downloading...');
-      window.onerror = function() {
-        Module.setStatus('Exception thrown, see JavaScript console');
-        spinnerElement.style.display = 'none';
-        Module.setStatus = function(text) {
-          if (text) Module.printErr('[post-exception status] ' + text);
-        };
       };
     </script>
     {{{ SCRIPT }}}
diff --git a/test/test_manual_wasm_instantiate.html b/test/test_manual_wasm_instantiate.html
index 101d61c85ae95..e8930994d6586 100644
--- a/test/test_manual_wasm_instantiate.html
+++ b/test/test_manual_wasm_instantiate.html
@@ -79,11 +79,6 @@
           if (element) element.value = ''; // clear browser cache
           return (...args) => {
             var text = args.join(' ');
-            // These replacements are necessary if you render to raw HTML
-            //text = text.replace(/&/g, "&amp;");
-            //text = text.replace(/</g, "&lt;");
-            //text = text.replace(/>/g, "&gt;");
-            //text = text.replace('\n', '<br>', 'g');
             console.log(text);
             if (element) {
               element.value += text + "\n";
@@ -91,57 +86,10 @@
             }
           };
         })(),
-        printErr: (...args) => {
+        printErr(...args) {
           var text = args.join(' ');
-          if (0) { // XXX disabled for safety typeof dump == 'function') {
-            dump(text + '\n'); // fast, straight to the real console
-          } else {
-            console.error(text);
-          }
+          console.error(text);
         },
-        canvas: (() => {
-          var canvas = document.getElementById('canvas');
-
-          // As a default initial behavior, pop up an alert when webgl context is lost. To make your
-          // application robust, you may want to override this behavior before shipping!
-          // See http://www.khronos.org/registry/webgl/specs/latest/1.0/#5.15.2
-          canvas.addEventListener("webglcontextlost", (e) => { alert('WebGL context lost. You will need to reload the page.'); e.preventDefault(); }, false);
-
-          return canvas;
-        })(),
-        setStatus: (text) => {
-          if (!Module.setStatus.last) Module.setStatus.last = { time: Date.now(), text: '' };
-          if (text === Module.setStatus.text) return;
-          var m = text.match(/([^(]+)\((\d+(\.\d+)?)\/(\d+)\)/);
-          var now = Date.now();
-          if (m && now - Date.now() < 30) return; // if this is a progress update, skip it if too soon
-          if (m) {
-            text = m[1];
-            progressElement.value = parseInt(m[2])*100;
-            progressElement.max = parseInt(m[4])*100;
-            progressElement.hidden = false;
-            spinnerElement.hidden = false;
-          } else {
-            progressElement.value = null;
-            progressElement.max = null;
-            progressElement.hidden = true;
-            if (!text) spinnerElement.hidden = true;
-          }
-          statusElement.innerHTML = text;
-        },
-        totalDependencies: 0,
-        monitorRunDependencies: (left) => {
-          this.totalDependencies = Math.max(this.totalDependencies, left);
-          Module.setStatus(left ? 'Preparing... (' + (this.totalDependencies-left) + '/' + this.totalDependencies + ')' : 'All downloads complete.');
-        }
-      };
-      Module.setStatus('Downloading...');
-      window.onerror = () => {
-        Module.setStatus('Exception thrown, see JavaScript console');
-        spinnerElement.style.display = 'none';
-        Module.setStatus = (text) => {
-          if (text) Module.printErr('[post-exception status] ' + text);
-        };
       };
 
       function downloadWasm(url) {
@@ -181,6 +129,6 @@
       var script = document.createElement('script');
       script.src = "manual_wasm_instantiate.js";
       document.body.appendChild(script);
-</script>
+    </script>
   </body>
 </html>