function test() {
    var id = document.getElementById("txtDnValue").value;
    $.ajax({
        type: "POST",
        async: false,
        url: "Test.aspx/test",
        data: "{ID:" + id + "}",
        dataType: "json",
        contentType: "application/json; charset=utf-8",
        success: function(msg) {
        }
    });
}