According to the documentation for the tag library, http://displaytag.sourceforge.net/11...reference.html
, it appears to be impossible.
What Struts does, which has similar functionality, is pass through values with identical parameter names. For example, <html:checkbox ... onClick="foo()"> would produce HTML like <input type="checkbox" ... onClick="foo()">. Perhaps you can lobby the developers of the displaytag project to implement a similar feature?
Adobe Systems, Inc.