title: getting this error " $.toJSON is not a function "
body: <p>I'm trying to use jQuery and Ajax and I use this method. but I get the error $.toJSON is not a function in my firebug . where is the problem? I use jquery 1.3.2 . thanks </p>
  
  <pre><code>  $(document).ready(function () {
          $("#S1").click(function 
              () {
              $("#t1").slideToggle("fast");
              $("#S1").css("background-color", "yellow");
              var ID = $("#HiddenField2").attr("Value");
              var params = new Object();
              params.Key = ID;
              $.ajax({
                  type: "POST",
                  url: "viewMessages.aspx/readen",
                  data: $.toJSON(params),
                  contentType: "application/json",
                  dataType: "json",
                  success: function () {
  
                  }
              });
          });
      });
  </code></pre>