unable to call web method of master page

I have a web method on  default.aspx.cs .. on master i have a button, on click of which i am calling the web method of default.aspx  on master page.. but the method is no calling,this is code of java script for it

<script type="text/javascript">

    $(document).ready(function() {
        $("[id*=feedbackbtn]").live("click", function() {
            var name = $('#fdTextBox1').val();
            var email = $('#fdTextBox2').val();
            var feedback = $('#fdTextBox4').val();
            var suggestion = "";
            var pageUrl = '<%=ResolveUrl("default.aspx")%>'


            $.ajax({
                type: "POST",
                url: pageUrl + "/postfeedback",
                data: "{'name':'" + name + "','email':'" + email + "','feedback':'" + feedback + "','suggestion':'" + suggestion + "'}",
                contentType: "application/json; charset=utf-8",
                dataType: "json"

            });

            $("#fdLabel4").html("Thanks for you FeedBack.");
            $('#fdTextBox1').val('');
            $('#fdTextBox2').val('');
            $('#fdTextBox4').val('');
            return false;


        });

    });
        
     
     </script>

this script is on master page but i am calling the method of default page ..

but if use same script on other page like default2.aspx its work , i dont know why its not working for mater page