Guys,

Either you treat stack as a stack, or as an array. What the heck is line:15 from your js solution? That's clearly accessing something by index.

            // While the temporary stack is not empty and the top element
            // of the temporary stack is greater than the current element,
            // push elements from the temporary stack back to the original stack.
            while (tempStack.length && tempStack[tempStack.length - 1] > temp) {
                stack.push(tempStack.pop());
            }