Once upon a time there was internet. You know, a bunch of computers all connected by wires. One person on a computer can read documents from another person is computer using a language called HTML.
Each computer’s web browser can properly display these documents. Add CSS to the mix and you’ve got a beautifully-styled web page. It is important to note that neither HTML nor CSS are programming languages.
Back in back in 1995 a few people at Netscape started to wonder, “What if there was a way to write a computer program for the browser?”This way, when HTML and CSS gets sent from one computer to another you can also send over some programming.