/JavaScript/build a web app with Nodejs

摘要

What's great is that if you've ever written browser JavaScript you already know about the event loop.When you want to make an Ajax request in the browser you request a file, and then you have to wait for it to happen. It's not immediate. Instead you give it a callback function that's executed when the response is received from the server. That's the event loop.You tell the browser that when the event of receiving a response happens it should call your function. You've almost certainly used onMouseOver or onLoad events too. Events are an essential part of working in the browser.