认识JSON

What is JSON?

Why does JSON matter?

How do we use JSON in a project?

We'll also use our newfound skills with JSON at the end of this project to build a quick app that loads photos from Flickr without requiring a page refresh.

What Is JSON?

JSON is short for JavaScript Object Notation, and is a way to store information in an organized, easy-to-access manner. In a nutshell, it gives us a human-readable collection of data that we can access in a really logical manner.

Why Does JSON Matter?

With the rise of AJAX-powered sites, it's becoming more and more important for sites to be able to load data quickly and asynchronously, or in the background without delaying page rendering. Switching up the contents of a certain element within our layouts without requiring a page refresh adds a "wow" factor to our applications, not to mention the added convenience for our users. Because of the popularity and ease of social media, many sites rely on the content provided by sites such as Twitter, Flickr, and others. These sites provide RSS feeds, which are easy to import and use on the server-side, but if we try to load them with AJAX, we run into a wall: we can only load an RSS feed if we're requesting it from the same domain it's hosted on.

JSON allows us to overcome the cross-domain issue because we can use a method called JSONPthat uses a callback function to send the JSON data back to our domain. It's this capability that makes JSON so incredibly useful, as it opens up a lot of doors that were previously difficult to work around.

http://www.copterlabs.com/json-what-it-is-how-it-works-how-to-use-it/