Javascript is the most popular and essential language for Web development. Not only for Web development but also for app development. Hence Frontend in Web development is incomplete without JS. HTML and CSS both are just a language, not programming languages, so we cannot perform any arithmetic as well as other logical operations through it but this is fulfilled by JS and it can be easily linked and executed with HTML and CSS. Though interactiveness in the Website exists due to JS.
This programming language was developed by "Brendan Eich" in 1995. He named this a "Mocha" sounds weird, but later it was renamed LiveScript. Hence initially LiveScript doesn't gain that much recognization. At that time JAVA was the most popular language. So to gain popularity in the programming world Livescript was renamed as Javascript simply Live was replaced by Java. By the way, Javascript and JAVA both are totally different languages with different syntax and programming structures. Thus JS became a necessity for all developers.
Benefits 0f JS
Javascript is also known as a loosely typed language which means it is faster and provides more flexibility to the developers. Unlike C++ it doesn't require specific data type inputs it accepts all data types such as integer, variable, boolean, float etc under one roof and it ignores the basic extra syntaxes.
Just like another programming language, it requires a compiler. So, various software provides a runtime environment for JS such as Node js. The output of JS is visible in Console. This can be directly accessed through Browser by going to Inspect element =>Console. Note all JS operations do not visible on the Page it consequences are only visible on the page.