code: function (url, success, fail) {
              _id ++;
              /*save jsonp success callback in gobal*/
              global[_jsonpwap + _id] = success || function () {};
              /*append "?" or "&" */
              url = net.urlfix(url);
  
              url += 'callback=' + _jsonpwap +_id;
              var script = document.createElement('script');
                  script.type = 'text\/javascript';
                  script.src = url;
  
              script.onload = function () {
                  script.remove();
              }
              script.onerror = function () {
                  fail && fail();
                  script.remove();
              }
              document.body.appendChild(script);
              /*chain call*/
              return net;
          }
docs: /*depens [@_id]