Wordpress ajax suffixer. (Need to work with WP chaching plugins like WP Super Cache, W3 Total cache, etc)If page has url "http://xmp.com/tax/tem/page-name" then ajax version of this page is "http://xmp.com/tax/tem/page-name/ajax"In template you can check AJAX request via const "IS_AJAX" (if (IS_AJAX){})

functions.php

<?php
/**
 * Detect ajax request
 */
add_filter('parse_request', function ($query_vars)
{
    if (is_admin())
    {
        return $query_vars;
    }

    $query = & $query_vars->query_vars;

    $is_ajax = false;

    if (!empty($query['is_ajax']))
    {
        if ($query['is_ajax'])
        {
            $is_ajax = true;
        }

        unset($query['is_ajax']);
    }

    if (!empty($query['ajax_page']))
    {
        $is_ajax = true;
    }

    define('IS_AJAX', $is_ajax OR !empty($_REQUEST['is_ajax']));

    if (IS_AJAX)
    {
        add_filter('redirect_canonical', function ($redirect_url, $requested_url)
        {
            return $requested_url;
        }, 10, 2);
    }

    return $query_vars;
}, 0);

function is_ajax_request()
{
    return defined('IS_AJAX') AND IS_AJAX;
}

/*
 * Ajax template redirection
 */
add_action('template_redirect', function ()
{
    if (is_ajax_request())
    {
        add_filter('template_include', 'ajax_template_include_action', 100, 1);
    }
});

function ajax_template_include_action($template_include)
{
    $suffix = (defined('AJAX_TEMPLATE_SUFFIX') AND constant('AJAX_TEMPLATE_SUFFIX')) ? AJAX_TEMPLATE_SUFFIX : 'ajax';

    //Try load template with [ajax] suffix
    //index-ajax.php, page-ajax.php, taxonomy-{name}-ajax.php, etc.
    $ajax_template = trailingslashit(dirname($template_include)) . basename($template_include, '.php') . "-$suffix.php";

    return is_file($ajax_template) ? $ajax_template : $template_include;
}

/**
 * Class WP_Ajax_Suffix_Templater
 *
 * Add '/ajax' suffix to al links, and load for such links templates
 */
class WP_Ajax_Suffix_Templater
{
    static $PREFIXES = array(
        'is_ajax' => array('is_ajax=1', 'ajax'), // http://xmp.com/page-base/ajax
        'ajax_page' => array('ajax_page=$matches[1]', 'ajax-page/(\d*+)'), // http://xmp.com/page-base/ajax_page/2
        /*'is_ajax_query' => 'is_ajax_query-[^/]+'*/
    );

    function __construct()
    {
        if (!static::$PREFIXES)
        {
            return;
        }

        add_filter('rewrite_rules_array', array(&$this, 'rewrite_rules_array_filter'), 100);
        add_filter('query_vars', array(&$this, 'query_vars_filter'));
        add_action('wp_loaded', array(&$this, 'wp_loaded_action'));
    }

    function prefixes_checksum()
    {
        static $prefixes_checksum = NULL;

        if ($prefixes_checksum !== NULL)
        {
            return $prefixes_checksum;
        }

        $prefixes = static::$PREFIXES;

        $prefixes_checksum = '';

        foreach ($prefixes AS $prefix => $rules_data)
        {
            $prefixes_checksum .= implode($rules_data) . $prefix;
        }

        return $prefixes_checksum = md5($prefixes_checksum);
    }

    function rewrite_rules_array_filter($global_rules)
    {
        $prefixes = static::$PREFIXES;

        $prefixed_rules = array();

        $prefixed_rules[self::prefixes_checksum()] = 'index.php';

        foreach($prefixes AS $prefix => $rule_data)
        {
            $query = $rule_data[0];
            $rule_pattern = $rule_data[1];

            $prefixed_rules["$rule_pattern/?$"] = "index.php?$query";

            foreach ($global_rules AS $global_rule => $global_query)
            {
                $global_rule = static::rule_rtrim_slash($global_rule);

                $prefixed_rules["$global_rule/$rule_pattern/?$"] =
                    rtrim($global_query, '&=') . '&' . static::prepare_query($global_query, $query);
            }
        }

        return array_merge($prefixed_rules, $global_rules);
    }

    function rule_rtrim_slash($rule)
    {
        return preg_replace('~/\?\$?$~iu', '', $rule);
    }

    function prepare_query($query, $appending_query)
    {
        $matches = array();

        if (preg_match_all('~\$matches\[(\d+)\]~iu', $query, $matches))
        {
            $max_match = max($matches[1]);
            $next_match = $max_match + 1;

            $appending_query = str_replace('$matches[1]', '$matches[' . $next_match .']', $appending_query);
        }

        return $appending_query;
    }

    function wp_loaded_action()
    {
        $rules = get_option('rewrite_rules');

        $prefixes_checksum = self::prefixes_checksum();

        if (empty($rules[$prefixes_checksum]))
        {
            global $wp_rewrite;

            $wp_rewrite->flush_rules();
        }
    }

    function query_vars_filter($vars)
    {
        foreach (static::$PREFIXES AS $prefix => $patter)
        {
            array_push($vars, $prefix);
        }

        return $vars;
    }
}

$WP_Ajax_Prefixes_Templater = new WP_Ajax_Suffix_Templater();