代码示例:(标识:js_set_create)
<!DOCTYPE html>
<html>
<body>
<h1>JavaScript Set</h1>
<p>将变量添加到 Set:</p>

<p id="demo"></p>

<script>
// 创建 Set
const letters = new Set();

// 创建变量
const a = "a";
const b = "b";
const c = "c";

// 将变量添加到 Set
letters.add(a);
letters.add(b);
letters.add(c);

// Display set.size
document.getElementById("demo").innerHTML = letters.size;
</script>

</body>
</html>
运行结果: