Application of Javascript.

1. Server applications -Node JS is built on Chrome's Javascript runtime for building fast and scalable network applications. This is an event-based library that helps in developing very cool server applications including Web Servers.
2. User Notifications - you can use JavaScript to make dynamic pop-ups to give different types of notifications to your website.
3. Back-end Data Loading - Javascript provides Ajax library which helps in loading back-end data while you are doing some other processing via frontend. This really gives an amazing experience to your website visitors
4. Client side validation - This is really important to verify any user input before submitting it to the server, Javascript plays an important role in validting those inputs at front-end itself to avoid submitting invalid creditials duriing authentication.
5. Manipulating HTML Pages - Javascript helps in manipulating HTML page on the fly. This helps in adding and deleting any HTML tag very easily using javascript and modify your HTML to change its look and feel based on different devices and requirements.