XML in a Nutshell, 3rd Edition

xlink:actuate

The optional xlink:actuate attribute has four possible values, which suggest when an application that encounters an XLink should follow it:

onLoad

The link should be followed as soon as the application sees it.

onRequest

The link should be followed when the user asks to follow it.

other

When to follow the link is determined by other markup in the document not specified by XLink.

none

No details are available about when or whether to follow this link. Indeed, following the link may not have any plausible meaning, as in the previous example where the link pointed to a book’s ISBN number rather than a URL where the book could be found.

All four of these are only suggestions, which browsers or other applications following XLinks are free to ignore. For example, a web spider would use its own algorithms to decide when to follow and not follow a link. Differing behavior when faced with the same attributes is allowed as long as it makes sense for the application reading the document.

For example, a traditional link, such as is provided by HTML’s A element and indicated by the first novel example, would be encoded like this:

<novel xlink:type="simple"
       xlink:href="ftp://archive.org/pub/etext/etext93/wizoz10.txt"
       xlink:actuate="onRequest" xlink:show="replace">
  <title>The Wonderful Wizard of Oz</title>
  <author>L. Frank Baum</author>
  <year>1900</year>
</novel>

This says to wait for an explicit user request to follow the link (e.g., by clicking on the content of the link) and then to replace ...