<!DOCTYPE html>
<html>
<body>
<h1>JavaScript 数组</h1>
<h2>flat() 方法</h2>
<p id="demo"></p>
<script>
const myArr = [[1,2],[3,4],[5,6]];
const newArr = myArr.flat();
document.getElementById("demo").innerHTML = newArr;
</script>
</body>
</html>