How to fetch data in .ashx(handler) page ?

Hi ,

I want to send session value to handler (.ashx) page.
I am calling Handler page in ajax call and sending data
I am placing code here

$.ajax({
            type: "GET",
            url: hn,
            dataType: "json",
            data: "{'AuthToken':'"+AuthToken+"','MileStoneId':'"+MileStoneId+"'}",
            contentType: "application/json; charset=utf-8",
            success: function(xData) {
                
                alert("hI");
                

                    var obj = eval(xData);
}
 });

here AuthToken and MileStoneId are session values

 var AuthToken = '<%=Session["AuthToken"]%>';
        var MileStoneId ='<%=Session["MileStoneId"]%>';

but in hadler When i am fetching that

string Authtoken = context.Request.QueryString["AuthToken"];
        int m = Convert.ToInt32(context.Request.QueryString["MileStoneId"]);

it returns null value.
please anybody tell me how to do that one..?

Thanks in advance

Happy Programming!!
Rohi