SPA is a web application or web site that fits on a single web page with the goal of providing a more fluid user experience similar to a desktop application. In a SPA, either all necessary code, HTML, JavaScript and CSS is retrieved with a single page load or the appropriate resources are dynamically loaded and added to the page as necessary, usually in response to user actions. This page is serving an iframe generated by retrogames.cc with the help of emulatorjs pakcage.