Changing array in JavaScript function changes array outside of function?

Question

Why the two scripts behave differently? I want the to use the first script, but in the second drawData() call it changes data; it\'s weird and not

Answer 1

First variant modifies object passed as parameter to function (which happens to be array) - so this change is seen outside function. Second variant assigns new value to function parameter (which happens to be reference to array) but does not change array itself.