Q. Is there an alternative to a pop-up box?
A. The preferred method is a pop-up box. It is also possible to put hover text or disclaimers to the same effect on the site.
oik-external-link-warning supports the hover text method for links where it’s not possible to display the pop-up alert.
For External links use the Hover selectors field to indicate the areas on the page on which the warning should be attached.
For Email links use the Email hover selectors field.