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<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript</h1>
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<p>可以通过将值设置为 <b>undefined</b> 来清空对象。</p>
​
<p id="demo"></p>
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<script>
let person = {firstName:"Bill", lastName:"Gates", age:19, eyeColor:"blue"};
person = undefined;
document.getElementById("demo").innerHTML = person;
</script>
​
</body>
</html>
​