JavaScript is a client-side scripting language and one of the most efficient interpreted languages. That means it gets executed line by line. Though It’s interpreted language it can handle the asynchronous tasks as well using web API, Callback Queue, and Event loop. It is a high-level computer programming language that runs inside an Internet browser. JavaScript mainly follows tree data structure.

Event handlers are used to handle events during the event bubbling cycle. A node may have one or more handlers for handling an event. In the case of the Web, events are connected inside the browser window and tend to be linked to a specific item that is inherent in it. It’s a runtime working method and creates a smooth user experience. Javascript uses single thread so that it happens asynchronously.

localStorage and sessionStorage are both same ways for browsers to store key/value pairs for a particular domain using the Web Storage API. But the main 3 diffrence are discribe in bellow.

#	Local stroage	Session stroage
1	The data stored in localStorage until expire	In Section stroage changes are only available per window
2	Local storage means Clint side stroage.	Section stroage means runtime stroage
3	We can save data by cookie and if we store data in server side we use session	We can stroge runtime which need one time.