Why are HTML frames bad?

Question

I know they are, but my co-worker doesn't believe me. He keeps telling me that Google crawls the inside content and caches it just fine. According to Google, it does crawl them, but doesn't guarantee doing it properly.

Any thoughts why frames are bad for public web sites?

Answer 1

There are various usability and accessibility issues with frames:

1. link can open in the frame it is enclosed in (e.g. a side pane);
2. can break the forward/backward navigation;
3. difficult to bookmark;
4. are not easily searchable (likely to see the content in Google, etc.);
5. break on browsers like Lynx, that are console/terminal based;
6. difficult to size properly (e.g. consuming height on widescreen monitors for banner frames);
7. can break with screen readers and magnifiers (for blind users and visual impaired users);

See http://www.angelfire.com/super/badwebs/ for an example of what not to do.