function my_func(){ var my_array = []; ...}
function other_func(){ ... my_array[2] = 5; ...}
function my_func(){ var my_array = []; other_func(my_array); ...//do something else with my_array which relies on the 3rd value being 5}function other_func(param){ param[2] = 5;}
function my_func(){ var my_array = []; my_array = other_func(my_array); ...//do something else with my_array which relies on the 3rd value being 5}function other_func(param){ param[2] = 5; return param;}
function f1(){ var arr = []; f2(arr); // what is arr now?}function f2(arr){ arr.push("pig"); arr = [];}