99.9% of all JavaScript is handling state and events in a user interface (web page). Ex: You have two buttons, and when both of them has been pressed, a image o

99.9% of all JavaScript is handling state and events in a user interface (web page). Ex: You have two buttons, and when both of them has been pressed, a image of a cat is displayed. >> functional event-driven code with contextual closures This paradigm works very well on the server side too. Ex: A HTTP requests makes a query to a database server, then returns the result to the browser This gives parallelism without the complexity of threads.