The important thing to remember is that struts tags are always rendered to regular html tags before they are displayed.
If you wish to write javascript to manipulate a
jsp page created with struts custom tags, the best way to do it is to make frequent use of the "view source" function of your browser. In IE, you just right-click the frame you're in and select "view source" from the context menu.
Once you look at the "View Source" output, you will then see the actual html that was redered by your struts tags. You will then know how to write the javascript to access those html controls because you will know how struts has named them.
Merrill