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<!DOCTYPE html>
<html>
<body>
<h1>JavaScript 变量</h1>
<h2>交换变量</h2>
<p id="demo"></p>
<script>
let firstName = "Bill";
let lastName = "Gates";
// 解构赋值交换变量
[firstName, lastName] = [lastName, firstName];
// 显示值
document.getElementById("demo").innerHTML = firstName + " " + lastName;
</script>
</body>
</html>