I'm trying to pass the reference of a control chart to my codebehind using PageMethods. Everything I've read says to use JSON, but nothing shows how to construct the object.

My Chart declaration is as bare bones as I could make it:

<asp:Chart ID="chFA1SM1" runat="server"></asp:Chart>

My javascript method looks like this, the ct declaration is my sad little attempt to construct my JSON object:

function getData() {
ct = {"ID": "chFA1SM1"};
PageMethods.getData(ct, function (returnValue) {
alert(returnValue.Name + ":" + returnValue.Value);
});
}

My WebMethod does get called; but when I try to convert this from an object to a chart, I get the following error at runtime:

Unable to cast object of type 'System.Collections.Generic.Dictionary`2[System.String,System.Object]' to type 'System.Web.UI.DataVisualization.Charting.Chart'.

The webmethod looks like this, very simple:

[WebMethod]
public static void getData(object ct)
{
Chart chrt = (Chart)ct;

LoadGraphFA1SM1();
}

So really, I guess I'm struggling in two areas:
1. Am I constructing the JSON object correctly in the javascript? (Pro'ly not)
2. Am I referencing it properly in the webmethod, the be working with the referenced value of the chart (obviously not).

I promise I've been Googling my butt off for the past day trying to find out how to d this, and my head now feels like mush and I think I'm missing the obvious

Thanks in advance.