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<html><body><h1>JavaScript Object Properties</h1><h2>Adding a new Property</h2><p id="demo"></p><script>const person = { firstname: "John", lastname: "Doe", age: 50, eyecolor: "blue"};person.nationality = "English";document.getElementById("demo").innerHTML =person.firstname + " is " + person.nationality + ".";</script></body></html>