[TYPO3-project-formidable] How to confirm at client?

[Thomas Schikarski]

Hi everybody,

I'm stuck at some point building a CRUD form.

I need a button that allows to close the edit form without saving 
changes, similar to this one:

<renderlet:SUBMIT name="btn-close" label="Close" mode="clear" />

However, I like to present a query box for confirmation: "Are you sure 
you want to close without saving your changes?"

Is this possible using something like the following XML inside the 
renderlet:SUBMIT?

	<onclick runat="client">
		<confirm>
			<userobj>
				
				... // should present query box like
				    // javascript:confirm('...');
			
			</userobj>
		</confirm>
		<userobj>

			... // should submit the form with mode="clear",
			    // in case of "OK" click

		</userobj>
	</onclick>

What do I have to put inside the <userobj> tags? Majix-Events? 
Javascript? PHP? Return value?

Any better ideas?

Best regards and many thanks in advance!