JSON (JavaScript Object Notation) is an open standard JavaScript syntax based on the subset of data exchange format. JSON is a text-based, lightweight, generally considered easy to read / write.
Popular explanations:
1.json is a data transmission format, the transmission data here generally refers to data interaction front and rear ends. For example, in the front fill out a form, the form may respond by HTML documents server to server, but the data is transmitted json format through interaction.
Front and back pages may not end json format, or post directly pass arguments to get the back end
2 static documents transmitted, the server responds directly to the browser is an HTML document