diff --git a/client/commonFramework/bindings.js b/client/commonFramework/bindings.js
index 37009a8a2a..158314255d 100644
--- a/client/commonFramework/bindings.js
+++ b/client/commonFramework/bindings.js
@@ -9,8 +9,7 @@ window.common = (function(global) {
     // ctrl + enter or cmd + enter
     if (
       e.keyCode === 13 &&
-      e.metaKey ||
-      e.ctrlKey
+      (e.metaKey || e.ctrlKey)
     ) {
       $('#complete-courseware-dialog').off('keydown', ctrlEnterClickHandler);
       if ($('#submit-challenge').length > 0) {
diff --git a/client/commonFramework/end.js b/client/commonFramework/end.js
index 139f6aad00..323b0d41f9 100644
--- a/client/commonFramework/end.js
+++ b/client/commonFramework/end.js
@@ -57,6 +57,11 @@ $(document).ready(function() {
       ({ err, solved, output, tests }) => {
         if (err) {
           console.error(err);
+          if (common.challengeType === common.challengeTypes.HTML) {
+            return common.updatePreview$(`
+              <h1>${err}</h1>
+            `).subscribe(() => {});
+          }
           return common.updateOutputDisplay('' + err);
         }
         common.updateOutputDisplay(output);
@@ -65,7 +70,7 @@ $(document).ready(function() {
           common.showCompletion();
         }
       },
-      (err) => {
+      ({ err }) => {
         console.error(err);
         common.updateOutputDisplay('' + err);
       }
@@ -76,8 +81,18 @@ $(document).ready(function() {
     return Observable.fromCallback($preview.ready, $preview)()
       .delay(500)
       .flatMap(() => common.executeChallenge$())
+      .catch(err => Observable.just(err))
       .subscribe(
-        ({ tests }) => {
+        ({ err, tests }) => {
+          if (err) {
+            console.error(err);
+            if (common.challengeType === common.challengeTypes.HTML) {
+              return common.updatePreview$(`
+                <h1>${err}</h1>
+              `).subscribe(() => {});
+            }
+            return common.updateOutputDisplay('' + err);
+          }
           common.displayTestResults(tests);
         },
         ({ err }) => {
diff --git a/server/views/coursewares/showVideo.jade b/server/views/coursewares/showVideo.jade
index ed06486f89..2368076288 100644
--- a/server/views/coursewares/showVideo.jade
+++ b/server/views/coursewares/showVideo.jade
@@ -65,8 +65,7 @@ block content
         function controlEnterHandler(e) {
             if (
               e.keyCode === 13 &&
-              e.ctrlKey ||
-              e.metaKey
+              (e.ctrlKey || e.metaKey)
             ) {
               $('body').unbind('keydown');
               $('#complete-courseware-editorless-dialog').modal('show');
@@ -76,8 +75,7 @@ block content
         function modalControlEnterHandler(e) {
           if (
             e.keyCode === 13 &&
-            e.ctrlKey ||
-            e.metaKey
+            (e.ctrlKey || e.metaKey)
           ) {
             $('#complete-courseware-editorless-dialog').unbind('keydown');
             $('#next-courseware-button').click();
diff --git a/server/views/coursewares/showZiplineOrBasejump.jade b/server/views/coursewares/showZiplineOrBasejump.jade
index 54d67cb844..f4936aed74 100644
--- a/server/views/coursewares/showZiplineOrBasejump.jade
+++ b/server/views/coursewares/showZiplineOrBasejump.jade
@@ -81,8 +81,10 @@ block content
 
       common.controlEnterHandler = function (e) {
         $('body').unbind('keydown');
-        if (e.metaKey && e.keyCode === 13 ||
-            e.ctrlKey && e.keyCode === 13) {
+        if (
+          e.keyCode === 13 &&
+          (e.metaKey || e.ctrlKey)
+        ) {
           $('#complete-zipline-or-basejump-dialog').modal('show');
         } else {
           $('body').bind('keydown', common.controlEnterHandler);
@@ -91,8 +93,10 @@ block content
 
       common.modalControlEnterHandler = function (e) {
         $('#complete-zipline-or-basejump-dialog').unbind('keydown');
-        if (e.metaKey && e.keyCode === 13 ||
-            e.ctrlKey && e.keyCode === 13) {
+        if (
+          e.keyCode === 13 &&
+          (e.metaKey ||  e.ctrlKey)
+        ) {
           $('#next-courseware-button').click();
         } else {
           $('#complete-zipline-or-basejump-dialog').on('keydown', common.modalControlEnterHandler);