Multiple use of ID on a page

If You've got more than one application of an ID on the page, be aware: IDs are only intended to be used just the once per page. For multiple custom selectors on a page, use a class if a descendent selector won't do the trick. Keeping your IDs to one per page is considered a best practice and in line with how CSS is supposed to work. Most, if not all, current browsers will still render your pages correctly, but you never know what going to happen in the future and why take the chance?