JSFiddle - React, Tailwind, and code Playground

by fatelei

HTML

<h1>JavaScript hasFocus example</h1>
<div id="message">Waiting for user action</div>
<div><button onclick="openWindow()">Open a new window</button></div>

JavaScript

setInterval( checkPageFocus, 200 );

function checkPageFocus() {
  var info = document.getElementById("message");

  if ( document.hasFocus() ) {
    info.innerHTML = "The document has the focus.";
  } else {
    info.innerHTML = "The document doesn't have the focus.";
  }
}

function openWindow() {
  window.open (
    "http://developer.mozilla.org/",
    "mozdev",
    "width=640,
    height=300,
    left=150,
    top=260"
  );
}