title: How to change browser focus from one tab to another
body: <p>I have a JavaScript chat client running in one browser tab (call it tab A). Now when a message arrives the user might be on another browser tab (call it tab B). I'm looking for ways to change the focus from tab B to my chat client (tab A) when such a message arrives. </p>
  
  <p>I could not find a way to do this. </p>