whoisgregg - 7:43 pm on Dec 3, 2012 (gmt 0)

This one is difficult to judge.

The rule of thumb with typical spiders is that they would only see "text" because it's in the alt attribute. But even that's iffy because they might ignore alt text in an <area> tag.

For Google, it's safe to say that they are running the javascript that the page pulls for a sufficient length of time to populate the page (and do whatever shady things spammers do like add redirects, hide text, etc.) then parse the resulting output as the true page.

But tooltips would only appear if they were simulating mouseover events for all the objects in the page. I don't know if any testing has been done on this.

Which, of course, brings us to the true answer, which is that you'd *need* to test a case like this to determine if it is being indexed.