pop 从末尾删除
shift 从前面删除
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
// pop 从末尾删除
// shift 从前面删除
var arr = [1,2,3,4];
arr.pop();//[1,2,3]
arr.shift();//[2,3]
console.log(arr)
</script>
</body>
</html>