function print_my_inline_script() {
  if ( is_product()) {
		?>
		<script type="text/javascript">
			jQuery('.auction_form.cart').submit(function() {
			    var c = confirm("Click OK to continue?");
			    return c; //you can just return c because it will be true or false
			});
		</script>
		<?php
  }
}
add_action( 'wp_footer', 'print_my_inline_script' );