[Solved] LightBox not working with jQuery

hello,

i have written code to call web service from javascript and write code but i got $.ajax uncaught is not defined function...error

why this is happening any idea?

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="AddToRackButton.ascx.cs"
    Inherits="PMKSoft.SLIM.Web.UserControls.AddToRackButton" %>
<%@ Import Namespace="PMKSoft.SLIM.Common" %>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script type="text/javascript">
    function GetBookReadValue() {
        debugger;
        var flag;
        $.ajax({
            type: "POST",
            url: '<%= ResolveClientUrl("~/IsReadWebService.asmx/IsRead") %>',
            data: "{MemberID:" + '<%= this.MembID %>' + ",ItemEditionID:" + '<%= this.ieid %>' + "}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            async: false,
            success: function (result) {
                flag = result.d;
            },
            error: function (request, status, error) {
                alert(request.responseText);
            }
        });
        return flag;
    }
</script>