Java Script is a computer programming language, which enables us to write the logic behind our code. Basically, If for example, you wrote a Web code and you used HTML and CSS for the skeleton body and design respectively. How you will write logic? here's the question arises what is logic? For example, you write any question on Google and "Press" enter. The function behind you clicking the enter button and Google taking you to the reasonable site you want is the logic behind pressing the button. So, JavaScript enables you to write this whole logic. In very simple words:- 
HTML:- Skeleton CSS:- Beauty JavaScript:- Brain
If you use all of these languages your site will have beauty with brain haha..

Java Script is a computer programming language, which enables us to write the logic behind our code. Basically, If for example, you wrote a Web code and you used HTML and CSS for the skeleton body and design respectively. How you will write logic? here's the question arises what is logic? For example, you write any question on Google and "Press" enter. The function behind you clicking the enter button and Google taking you to the reasonable site you want is the logic behind pressing the button. So, JavaScript enables you to write this whole logic. In very simple words:-  
  
HTML:- Skeleton  
CSS:- Beauty  
JavaScript:- Brain

If you use all of these languages your site will have beauty with brain haha..

What is JavaScript? Easy and simple.