object as a parameter in javascript

1function foo() {
2  for (var i = 0; i < arguments.length; i++) {
3    console.log(arguments[i]);
4  }
5}
6
7foo(1,2,3);
8//1
9//2
10//3

1function myFunction(x, y) {
2  if (y === undefined) {
3    y = 2;
4  }
5}

1var fac = function me(n) {
2    if (n > 0) {
3        return n * me(n-1);
4    } else {
5        return 1;
6    }
7};
8console.log(fac(3)); // 6