30 ms·

-

• jonatanheyman 9y ago
  JavaScript doesn't break if you don't supply all arguments in a function call.
  • deleted 9y ago
    [deleted]
• adambrenecki 9y ago
  'a' and 'm' are assigned to in the body of the function. Having them as arguments that aren't provided (and thus initially set to undefined) just ensures that they can be assigned to without 'var', saving a character or two.