<!DOCTYPE html>
<html>
<body>
<h1>JavaScript 数组</h1>
<p>length 属性设置或返回数组中元素的数量。</p>
<p id="demo"></p>
<script>
const fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits.length;
</script>
</body>
</html>