I found wonderfull article, which explain how to use pushState with AJAX. https://moz.com/blog/create-crawlable-link-friendly-ajax-websites-using-pushstate
But I can't figure out how organized "content.php" file. In comments this question is often asked, but nobody answered to this. This is quite important, because without "content.php" nothing works.
May be somebody know the example of "content.php"? I will appreciate it. Thanks