Highslide's AJAX engine lets you put your content in a separate file and display
it within a Highslide popup. If the file is HTML, you can specify a specific id
for Highslide to fetch. In this case, the id intro was fetched.
To see the source of the linked AJAX file, right click on the anchor link that you clicked to open this popup, then choose Open in new window.
Highslide caches the AJAX content upon page load, so that it sits ready to display instantly when the user clicks the thumbnail or link.