For example, I seem to get this a lot, you build a website using a Strict XHTML doctype and then clients start to ask you to put popup links in (target=”_blank”) now we all know that this goes against the strict doctype and doesn’t validate, but when I object to my clients, well, they still want this feature.

On reflection perhaps it’s not such a bad thing anyway, a lot of times a link will open a pdf and lots of users close the window expecting to return to their web browser, but actually end up closing their browser altogether.

Instead of putting the focus on web developers, perhaps we should ban these browser add-ins as a worse barrier to usability than target=”_blank” links, which in this example may improve usability…

I know I can switch to the transitional doctype to get round this, but generally I’d prefer not to have to.

I also understand that XHTML was developed to work across a number of applications / devices and therefore target=”_blank” may not be great for pdas or mobile phones, but neither is a pdf document which most mobile phone users can’t (yet) open.