What is js?
* Javascript was designed to add interactivity to HTML pages
* Javascript is a scripting language
* A scripting language is a lightweight programming language
* Javascript is usually embedded directly into HTML pages
* Javascript is an interpreted language (means that scripts execute without preliminary compilation)
* Everyone can use Javascript without purchasing a license.

Are JAVA and JAVAscript the same?

NO!

Java and Javascript are two completely different languages in both concept and design!

Java (developed by Sun Microsystems) is a powerful and much more complex programming language - in the same category as C and C++.

What can a JS do?

* Javascript gives HTML designers a programming tool - HTML authors are normally not programmers, but Javascript is a scripting language with a very simple syntax! Almost anyone can put small "snippets" of code into their HTML pages
* Javascript can put dynamic text into an HTML page - A Javascript statement like this: document.write("

" + name + "

") can write a variable text into an HTML page
* Javascript can react to events - A Javascript can be set to execute when something happens, like when a page has finished loading or when a user clicks on an HTML element
* Javascript can read and write HTML elements - A Javascript can read and change the content of an HTML element
* Javascript can be used to validate data - A Javascript can be used to validate form data before it is submitted to a server. This saves the server from extra processing
* Javascript can be used to detect the visitor's browser - A Javascript can be used to detect the visitor's browser, and - depending on the browser - load another page specifically designed for that browser
* Javascript can be used to create cookies - A Javascript can be used to store and retrieve information on the visitor's computer


credits:w3schools
and also to God <3