diff --git a/plugin/multiplex/master.js b/plugin/multiplex/master.js
index 60d546b0..7f4bf451 100644
--- a/plugin/multiplex/master.js
+++ b/plugin/multiplex/master.js
@@ -20,7 +20,7 @@
 	};
 
 	// post once the page is loaded, so the client follows also on "open URL".
-	window.onload = post;
+	window.addEventListener( 'load', post );
 
 	// Monitor events that trigger a change in state
 	Reveal.addEventListener( 'slidechanged', post );