<!DOCTYPE html>
<html>
<body>
<h2>JavaScriptオブジェクトのプロパティ</h2>
<p>オブジェクト・プロパティの削除</p>
<p id="demo"></p>
<script>
const person = {
firstname: "John",
lastname: "Doe",
age: 50,
eyecolor: "blue"
};
delete person["age"];
document.getElementById("demo").innerHTML =
person.firstname + " は " + person.age + " 歳です。";
</script>
</body>
</html>
