Looking some more at the source code, I wonder if perhaps I should have my JS code call A4J.AJAX.Submit() directly. I need to figure out what the params of that are and how to use it but it might be an option. I set up a test page with a <h:inputText> with a nested <a:support>, and that worked. It had a form with the right enctype. I changed <h:inputText> to <s:fileUpload>, and changed nothing else on the page, and it didn't work. Obviously the <a:support> tag isn't putting any kind of onchange attribute on the enclosing <s:fileUpload> tag. I assume this is a bug? There aren't any other Seam UI controls that are inputs, so maybe this hasn't been tested in Seam. But I think it's a bug. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4077597#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...