[TYPO3-project-formidable] JS confirm before button onclick

[Nikitin S.M.]

Is it possible to open a JS confirm box (with yes|no) using builtin 
onlick server/ajax configuration
like:
I need user to confirm delete action if he'll do mistake
name = deleteButton
onclick{
	runat = server
	params = someParams
	userobj.php(
		//DO SOMETHING
	)
}