How to show / hide multiple elements at the same time with javascript

Question

So, I have this between my head tags

Answer 1

Difference between display and visible:

• An element that is visible still takes up space on the page. The adjacent content is not rearranged when the element is toggled between visible and hidden.
• An element that is display=none will not take up any space on the page. Other display values will cause the element to take up space. For example, display=block not only displays the element, but adds line breaks before and after it.