Update JavaScript.md

JavaScript.md

@@ -540,7 +540,7 @@ PrefixedEvent(anim, "AnimationStart", AnimationListener);
 - Web Workers - An API for defining background scripts to run concurrently from the main thread handling user interactions. IE10+ See http://www.html5rocks.com/en/tutorials/workers/basics/
 - WebSockets - Allows the browser to open 2 way communication with the server this allows real time communication rather than relying on polling. (More Info  https://developer.mozilla.org/en-US/docs/WebSockets/Writing_WebSocket_client_applications)
 - Server Side Events(SSEs) - 
-- Page Visibility - Using document.hidden and/or document.visibilityState you can determine whether the page is in the active tab of the browser and whether the browser window is minified or not
+- Page Visibility - Using document.hidden and/or document.visibilityState you can determine whether the page is in the active tab of the browser and whether the browser window is minified or not. IE10+
 
 ```javascript
 function handleVisibilityChange() {