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<html><body><h1>The Window Object</h1><h2>The closed Property</h2><p><button onclick="openWin()">Open "myWindow"</button></p><p><button onclick="closeWin()">Close "myWindow"</button></p><p><button onclick="checkWin()">Is "myWindow" closed?</button></p><div id="demo"></div><script>let myWindow;function openWin() { myWindow = window.open("", "myWindow", "width=400,height=200");}function closeWin() { if (myWindow) { myWindow.close(); }}function checkWin() {let text = "";if (!myWindow) { text = "It has never been opened!";} else { if (myWindow.closed) { text = "It is closed."; } else { text = "It is open."; }}document.getElementById("demo").innerHTML = text;}</script></body></html>