Used in Web pages, JavaScript is a "client-side" programming language,it is mainly used for gives client side validation, This means JavaScript scripts are read, interpreted and executed in the client, which is your Web browser. By comparison, "server-side" programming languages run on a remote computer, such as a server hosting a website.
HTML: Hypertext Markup Language well known word to everyone & CSS Cascading Style Sheet, both are core technologies for build the Web pages. HTML provide structure to overall the page and css provide style to content(images & text) and makes consistency to pages.
JavaScript: JavaScript is one of the language use with HTML. It is Lightweight, interpreted, Object-Oriented language and known as SCRIPTING LANGUAGE.
Front End DesignerWeb Developer or web application Developer Directlty work for ecommerce company, Bloging Websites, Online news paper/articlesTemplate Designer Logo maker Content WriterThere are so many factors you can work in any software company.