Ajax跨域请求

 $.ajax({
                async: false,
                url: "http://list.qq.com/cgi-bin/qf_compose_send",
                type: "GET",
                dataType: 'jsonp',
                contentType: "application/x-www-form-urlencoded; charset=gb2312",
                jsonp: 'jsoncallback',
                data: d,
                timeout: 5000,
                beforeSend: function() { },
                error: function(xhr) {
                    alert(xhr);
                },
               success: function() {
                    alert("success");
                }
                      });