arguments[0]()的详解

var length = 10;

    function fn(){
        console.log(this.length);
    }

    var obj = {
        length:5,
        method:function(fn){
            fn();
            arguments[0]();
        }
    }

    obj.method(fn,1);

结果为10   2

arguments[0]() => fn() =>this指向arguments所以输出arguments.length