Most modern web pages are not just static. They often get updates from the server without interaction from the user. For example, your Twitter or Gmail browser client will display new tweets or e-mails without you reloading the page. The server pushes the information via WebSockets ( https://en.wikipedia.org/wiki/WebSocket ), and Action Cable provides the tools you need to use these mechanisms without diving deep into the technical aspects of WebSockets.
The use of Action Cable always includes JavaScript, and this book is about Ruby and Ruby on Rails. So, I will only show you a minimal Hello ...
