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<html><body><h1>The Window Object</h1><h2>The self and top Properties</h2><p id="demo"></p><script>let text;if (window.top != window.self) { text = "This is not the topmost window! Am I in a frame?";} else { text = "This is the topmost window!";} document.getElementById("demo").innerHTML = text;</script></body></html>