Ajax

Ajax is short for Asynchronous Javascript and XML, which refers to a set of web development techniques rather than an actual programming language. Ajax however, is widely used in client-side programming (e.g. Javascript) to allow for data to be sent and received to and from a database / server. What’s special about using Ajax programming is that you can exchange data in the background without actually disturbing the user experience. As Wikipedia puts it, By decoupling the data interchange layer from the presentation layer, Ajax allows for web pages, and by extension web applications, to change content dynamically without the need to reload the entire page. This method is extremely useful both for website performance and usability. Since asynchronous loading is non-render blocking, it will allow your page’s HTML to continue parsing even if it encounters a script tag. From a usability standpoint, visitors can benefit from seeing certain information generated without having to reload the page. This is a huge step forward for improving perceived performance.