How JSOM working in SharePoint

Think of JSON as the means of exchanging data between your SharePoint elements and Business Logic. CSOM queries are passed into SharePoint as XML, and the return values are in form of JSOM. It works by means of [[Key:value]] pair. This image below explains the idea - 

 

 

 

 

It is based on the subset of JavaScript. It is very lightweight and fast 

http://www.json.org/

Hi,

 

Refer below tutorials

 

http://www.dotnetcurry.com/sharepoint/1028/sharepoint-apps-javascript-object-model-jsom

 

https://msdn.microsoft.com/en-us/library/office/hh372944(v=office.14).aspx