Question

I am sure i am doing something bad here, but i cannot figure out what.

  <script type="text/javascript">
        $(function () {
            $("li").bind("click", function () {
                var sel = $(this).attr('id').toString();
                $.ajax({

                    type: "POST",
                    contentType: "application/json",
                    data: sel,
                    url: "Default.aspx/SaveValue",
                    dataType: "text",
                    success: function (data) {
                        alert(data.d);
                    },
                    error: function (XMLHttpRequest, textStatus, errorThrown) {
                        debugger;
                    }
                });
            });
        });
    </script> 

Any advises please?
And here is the debug info gathered

UPDATE: By changing to data: "{var1:'test'}", and dataType: "json", everything works as expected

Answer 1

By changing to data: "{var1:'test'}", and dataType: "json", everything worked as expected.
Special thanks to Sparky and to all commenters of course