Reported by jteh on 2008-03-18 23:15
It is possible to have a link with no content, like so:

<a href="#"></a>

This is pretty silly, but it is nevertheless possible and you can actually tab to such a link.

Unfortunately, the gecko_ia2 backend does not render these empty link objects into the text at all; i.e. they have a length of 0 characters. This causes two problems:

• The user cannot access the link by cursoring in the virtual buffer, but pressing k before the link will jump to the supposed start location of the link and say "blank".
• If the last rendered element in a document is an empty link, links list will cause a crash in Firefox and a lockup in NVDA.
  • This is because the start offset is actually one past the end of the buffer. When the iterator tries to check for a further link, it passes this invalid offset to the buffer and causes a crash.
  • The iterator could perform bounds checking to ensure this doesn't happen, but I'm wondering whether this should be done in storage to prevent similar crashes.

Proposed Solutions

• The gecko_ia2 backend could expose empty links as a single space character, similar to the way other empty elements such as graphics and checkboxes are exposed. I think this is the preferred solution.
• The NVDA code to jump to links and the node iterator could ignore 0 length nodes. This would also require the bounds checking described above, either in NVDA or storage.

Test Cases

• See attachment; causes links list crash.
• http://www.gennarino.org/forum; causes links list crash.