diff --git a/.github/workflows/js.yml b/.github/workflows/js.yml
new file mode 100644
index 00000000..517112f7
--- /dev/null
+++ b/.github/workflows/js.yml
@@ -0,0 +1,24 @@
+name: Node.js CI
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [8.x, 10.x, 12.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm install
+    - run: npm run build --if-present
+    - run: npm test
+      env:
+        CI: true
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index e65e0df4..00000000
--- a/.travis.yml
+++ /dev/null
@@ -1,5 +0,0 @@
-language: node_js
-node_js:
-  - 11
-after_script:
-  - npm run build -- retire
diff --git a/README.md b/README.md
index 1e65ad3a..b2557652 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,10 @@
 
 A framework for easily creating beautiful presentations using HTML. [Check out the live demo](https://revealjs.com/).
 
-reveal.js comes with a broad range of features including [nested slides](https://github.com/hakimel/reveal.js#markup), [Markdown contents](https://github.com/hakimel/reveal.js#markdown), [PDF export](https://github.com/hakimel/reveal.js#pdf-export), [speaker notes](https://github.com/hakimel/reveal.js#speaker-notes) and a [JavaScript API](https://github.com/hakimel/reveal.js#api). There's also a fully featured visual editor and platform for sharing reveal.js presentations at [slides.com](https://slides.com?ref=github).
+reveal.js comes with a broad range of features including [nested slides](https://github.com/hakimel/reveal.js#markup), [Markdown support](https://github.com/hakimel/reveal.js#markdown), [PDF export](https://github.com/hakimel/reveal.js#pdf-export), [speaker notes](https://github.com/hakimel/reveal.js#speaker-notes) and a [JavaScript API](https://github.com/hakimel/reveal.js#api). There's also a fully featured visual editor and platform for sharing reveal.js presentations at [slides.com](https://slides.com?ref=github).
+
+### Supporting reveal.js
+This project was started and is maintained by [@hakimel](https://github.com/hakimel/) with the help of many [contributions from the community](https://github.com/hakimel/reveal.js/graphs/contributors). The best way to support the project is to [become a paying member of Slides.com](https://slides.com/pricing)—the reveal.js presentation platform that Hakim is building.
 
 
 ## Table of contents
diff --git a/js/reveal.js b/js/reveal.js
index 0458fc77..b9775ae6 100644
--- a/js/reveal.js
+++ b/js/reveal.js
@@ -32,8 +32,12 @@
 		HORIZONTAL_SLIDES_SELECTOR = '.slides>section',
 		VERTICAL_SLIDES_SELECTOR = '.slides>section.present>section',
 		HOME_SLIDE_SELECTOR = '.slides>section:first-of-type',
+
 		UA = navigator.userAgent,
 
+		// Methods that may not be invoked via the postMessage API
+		POST_MESSAGE_METHOD_BLACKLIST = /registerPlugin|registerKeyboardShortcut|addKeyBinding|addEventListener/,
+
 		// Configuration defaults, can be overridden at initialization time
 		config = {
 
@@ -1311,11 +1315,20 @@
 
 					// Check if the requested method can be found
 					if( data.method && typeof Reveal[data.method] === 'function' ) {
-						var result = Reveal[data.method].apply( Reveal, data.args );
 
-						// Dispatch a postMessage event with the returned value from
-						// our method invocation for getter functions
-						dispatchPostMessage( 'callback', { method: data.method, result: result } );
+						if( POST_MESSAGE_METHOD_BLACKLIST.test( data.method ) === false ) {
+
+							var result = Reveal[data.method].apply( Reveal, data.args );
+
+							// Dispatch a postMessage event with the returned value from
+							// our method invocation for getter functions
+							dispatchPostMessage( 'callback', { method: data.method, result: result } );
+
+						}
+						else {
+							console.warn( 'reveal.js: "'+ data.method +'" is is blacklisted from the postMessage API' );
+						}
+
 					}
 				}
 			}, false );