This function allows you to trigger a function of your own when text has been unselected on the displayed document.
Parameters
- docuViewareID
 - The identifier for the DocuVieware™ instance.
 - callback
 - The function you want to execute on event.
 
Return Value
1 if error. 
Example of usage
This JavaScript makes sure the DocuVieware control is properly loaded and initialized and then subscribes to the event on load.