JSON, a way to represent data in JavaScript, has spread well beyond its humble origins and has now received the official accolade of an ECMA standard. 

JSON - JavaScript Object Notation - is such a simple idea that once you have seen it then there seems to be no reason not to use it or to seek something more complicated. It was originally specified and popularized by Douglas Crockford. Until now, however, the only standard relating to it was RFC 4627. 

The basic idea of JSON is to package data as a JavaScript object. For example:

{  "firstName":"Douglas",
   "lastName":"Crockford"
}

This can be regarded as abstract markup, like XML say, or it can be read as a fully functioning JavaScript object, which can be instantiated using the Eval function. Of course, the big problem is that if JSON is received from an untrusted source it might contain JavaScript methods as well as properties, which is a potential security problem. To stop this happening JSON idoesn't let you use just any JavaScript object you care to create, but defines a restricted set which allows building static data structures. 

In JSON you can have numeric, string and Boolean values. You can also have Arrays and objects. You can also use null to indicate no data. This is fairly restrictive but usually more than enough to code up data to be sent serially across a connection or returned by an API etc. 

The new ECMA standard is number 404, a value that has raised the worry that it might be some sort of elaborate joke - 404 being the well- known Page not found HTTP error. It formalizes the restrictions and extensions of JSON over native JavaScript.  The idea is that you can parse the JSON to check that it is valid and then make use of it without having to worry about security problems.

In practice, of course, we have been able to do this for some time in JavaScript using the JSON object, either provided natively in the browser or via a library. The standard is also important for JSON's increasing support in languages other than JavaScript where the notation isn't natively supported. 

In a very short time JSON has overtaken XML as the standard data markup for the web. In combination with Ajax and REST it has also overtaken the overly complex SOAP Remote Procedure call.