Internal properties of JS inside function

1.arguments is used to store the collection of transmission parameters, can be called multiple times, each time the group is different, enhancing the robustness of the function

Instance:

Function Calc () {
     var sum = 0;
     /* parameter is a time */
     if (arguments.length = = 1) {
         sum = arguments[0]
     } else if (arguments.length = = 2) {
         /* When the parameter is two */
         for (var i = arguments[0]; I <= arguments[1]; i++) {
             sum + = i;
         }
     }
     return sum;
}

Console.log (calc); The//calc function can be called multiple times, and the number of arguments passed in can be different.
Console.log (Calc (10, 20));

2.This iscalled by the function who is this, the method is called when the function is preceded by a window, just omitted

var person = {};
Person.name = "fangming";
Person.cals = Calcone;
var resultone = Person.cals ();

function Calcone () {
    Console.log (this);//This is the value inside the person array
    var sum = 0;
    for (var i = 0;i <= 10;i + +) {
        Sum+=i;
    }
    return sum
}

Internal properties of JS inside function