//BUY NOW confirmation JS

function print_my_secondline_script() {
  if ( is_product()) {
		?>
		<script type="text/javascript">
			jQuery('.single_add_to_cart_button.button').click(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_secondline_script' );