Ahogy Michael Kuehl irja:
The arguments
array is a special array that gets set when you enter a function call in javascript. The only thing special about it, though, is that it holds all the arguments that the function was called with - other than that it acts like a normal array.
…
Also, the arguments
array is not read only. This means that you can alter its contents, or even clear the array itself.
…
And if you modify the arguments
array itself (i.e, in this case set it to null), you loose the ability to access the arguments through the arguments
array, but it doesn’t affect any of the actual variables.