----arguments
When the function is called every time the browser passed into two implicit parameters,
A context object function, this
Argument 2 encapsulated object arguments
arguments array object is a class, may be operated Laid index data may be acquired length,
We passed arguments will be saved in the arguments in the function call,
arguments.length arguments can be used to obtain the length.
Even if we do not define parameter arguments may be used by only troublesome arguments, argument [0] indicates the first argument.
arguments callee property This property corresponds to a function object, the object function is currently being executed.