return null with query string whtn i use ajax-jquery

Question

this is my jquery code:

<script type="text/javascript">
    $(document).ready(function () {
        $("a").hover(function () {

            $.ajax({
                type: "POST",
                url:"Dbread.aspx",

                data: "name=salam",
                success: function (result) {
                    alert(result);


                } //end of success




            });


        }, function () {



        });


    });

</script>

in Dbread.aspx i wrote:

      string str= Request.QueryString["name"];
    Response.Write(str);

but the problem is that query string result is null all times!!! what is problem?