The answer to this question is almost always “yes”. This is mainly because it doesn’t matter how the page is manipulated, only that FullStory sees the results of those changes.
To verify this statement, here is a little more on how it all works.
If you’ve ever built or modified a website, then you’ve seen HTML. The tags in HTML (e.g., <p>Here’s a paragraph.</p>) generate what are called Document Object Model elements (DOM elements, for short). The styles applied to these elements (size, colors, borders, background images, and so forth) are defined by Cascading Style Sheets, or CSS. Dynamic sites (often referred to as AJAX) work by running code in Javascript to manipulate these elements in response to user interactions.
We realized that if we record all DOM elements, along with their associated CSS styles, then we can reproduce a static web page precisely. Then, if we can record all changes to the page, we can reproduce a dynamic web page just as precisely. So that’s exactly what FullStory does.
Here’s a partial list of interesting things (apart from the basics) that FullStory can record:
Notably absent from the things FullStory records is any mention of Javascript or data retrieved from the server. We needn’t record any of this, because anything the user actually saw is, by definition, represented in changes to DOM elements on the web page. The answer is therefore, "Yes", we can work with your site no matter how it is written.
Alas, there are still a few things we can't do. This isn't necessarily an exhaustive list, since new technology is constantly popping up, but these are the most commonly requested: