When JavaScript was created it's initial name was "LiveScript" with purpose to "make webpages alive" . As JavaScript evolved it became a fully independent language, with its own specification called ECMAScript . Recent versions are referenced by their ECMAScript version number(ES5, ES6). More recently the standards body has transitioned to a year-based number(ES2016, ES2017). Use source attribute to attach script files to HTML. The benefit of having separate files(rather than writing the whole script directly in html) besides readability is that the browser will download it and then store in its cache. After this, other pages that want the same script will take it from the cache instead of downloading it. So the file is actually downloaded only once. A single script tag can’t have both the src attribute and the code inside. A variable in JavaScript can contain any data. A variable can at one moment be a string and later receive a numeric value: Progr...