JavaScript is most popular, commonly used, object-oriented, client-side scripting language. JavaScript widely used in tasks ranging from the form data validation to the development of enhanced user interfaces and dynamic websites. The primary use of Client-side JavaScript is to write functions that are embedded in or included from HTML pages and interact with the Document Object Model (DOM) of the page. Because JavaScript code can run locally in a user’s browser (instead of get parse on a remote server like PHP or ASP.NET), it can respond to user actions quickly, making an application feel more responsive and user friendly.