JS——arguments

1、只在函数中使用

2、返回的是实参的数组

<script>
    getNum(1, 2);//(2) [1, 2, callee: ƒ, Symbol(Symbol.iterator): ƒ]
    getNum(1, 2, 3);//(3) [1, 2, 3, callee: ƒ, Symbol(Symbol.iterator): ƒ]
    getNum(1, 2, 3, 4);//(4) [1, 2, 3, 4, callee: ƒ, Symbol(Symbol.iterator): ƒ]
    console.log(getNum.length);//形参的个数
    function getNum(a, b) {
        console.log(arguments);
        console.log(arguments.length);//实参的个数
    }
</script>