[TRINIDAD] How to display "Page loading..." while page is loading?

[Paul Spencer]

I have an action that takes a few seconds to complete.  I would like the 
user to see something link "Page loading..." while the action is 
processing.  The action loads a List from a series of database queries 
and the page simply displays the list in a table.  Looking at the 
examples, it appears that <tr:statusIndicator"> is part of the answer.

My question is how should I do this?
Paul Spencer