jquery - Obtaining a Return Value - AJAX -

with code snippet below, returning value in ajax, checking return value. problem experiencing returns "undefined".

function loadusercontrol() {         var i;          $.ajax({             type: "post",             url: "form.aspx/load",             data: "",             contenttype: "application/json; charset=utf-8",             datatype: "json",             success: function (r) {                 alert(r.d);// values                 var data = $.parsejson(r.d);                 var projectid = data.projectid;                 alert(projectid );//undefined                 (i = 0; < r.d.length; i++) {                     paramlist = "{'fieldtypename':'" + data.fieldtypename + "'}";                     if (paramlist == "textbox") {                         alert();                     }                 }             }         });      }