RGraph reload the previous graph when i reload the page and i click the body of the page

You need to clear the ObjectRegistry, which keeps track of objects. You can do that with:

RGraph.ObjectRegistry.Clear();

Or you can clear objects related to a specific canvas tag with:

RGraph.ObjectRegistry.Clear(myCanvas);

Or you can remove a specific object with:

RGraph.ObjectRegistry.Remove(myObject);

You can read more about the ObjectRegistry on the API docs page:

https://www.rgraph.net/canvas/api.html#objectregistry

You can also use RGraph.Clear(document.getElementById("The Id of your element"));