css div id used only once per page

Question

In using CSS is it best practice to use a div id only once per page. I know each id has to be unique but could be used multiple times. A discussion with my development tea

Answer 1

It is physically possible to have duplicate id's per page, but the reason you only want to use one id per page with CSS is because of CSS selectors. Doing a CSS select by id is expected to only return a single DOM item.