code: function (params) {
                  var element = document.createElement('script'),
                      headElement = document.getElementsByTagName('head')[0],
                      load = params.load,
                      error = params.error,
                      jsonpCallback = params.jsonpCallback,
                      timeout = params.timeout || 10000,
                      timeoutId,
                      handleError = function (err) {
                          window.clearTimeout(timeoutId);
                          delete window[jsonpCallback];
                          headElement.removeChild(element);
                          if (error) {
                              error("500", {message: err});
                          }
                      };
  
  
                  window[jsonpCallback] = function (data) {
                      window.clearTimeout(timeoutId);
                      // TODO: add response validation here
                      load("200", data);
                      delete window[jsonpCallback];
                      headElement.removeChild(element);
                  };
  
                  // Error handlers fall back to timeout.
                  element.onerror = handleError;
                  element.onreadystatechange = function () {
                      var readyState = element.readyState;
                      if (readyState !== 'loaded') {
                          handleError({type: 'error'});
                      }
                  };
                  timeoutId = window.setTimeout(handleError, timeout, 'timeout');
  
                  element.type = 'text/javascript';
                  element.src = this.updateQueryString(params.jsonpUrl, params.callbackName, jsonpCallback);
                  element.id = jsonpCallback;
                  element.async = true;
                  element.charset = 'utf-8';
  
                  headElement.appendChild(element);
              }
docs: Adds script tag to header of page to make jsonp request and invokes the callback.
  @param {object} params