I would like to save the drawing graph, so that when the page is refreshed, the graph does not disappear .I want also add a zoom effect on the neouds and add a hint to the link number.
Is there a sample of this kind.
There are many samples that demonstrate saving a diagram by serializing and saving its model. Many samples demonstrate this without using the server by storing the result of Model.toJson in a textarea on the page itself, just so that you can see the serialized text, and so that you can modify it there and load it as a new diagram. Of course in your app you probably want to save the model on your server, and that will depend on how you communicate with your server – GoJS does not impose any requirements along those lines.
What do you mean by “zoom effect on the nodes”? What do you mean by “a hint to the link number”? Some screenshots or sketches would be helpful as well as a detailed textual description of what you would like.