idxbroker-wrapper-tags.php

<?php
// Always add idx tags to wrappers
add_filter ('the_content', 'idxbroker_add_idx_tags', 99);

   function idxbroker_add_idx_tags($content) {

	    	global $post;
		    $idxstart = '<div id="idxStart" style="display: none;"></div>';
		    $idxstop = '<div id="idxStop" style="display: none;"></div>';

			if (  is_singular('idx-wrapper') ) {

		   			$content = $content . $idxstart . $idxstop;

		       }
// Returns the content.
return $content;

    }