In the site
http://www.amcharts.com/demos/
I found that they are providing way to edit the demos in jsfiddle but for every demo the jsfiddle.net link remains the same as follows
I guess they are referring jsfiddle.net with some post data. Though i'm not sure about that. Any idea how it can be achieved.
I believe this is what you're looking for. It describes the ways to display a fiddle from query data. Here's an excerpt explaining why the URL remains the same.
Use library/pure for no framework:
URL: jsfiddle.net/api/post/library/pure/