code: function( local ) {
              // IE11 does not support window.ActiveXObject so we just try to
              // create one to see if it is supported.
              // See: http://msdn.microsoft.com/en-us/library/ie/dn423948%28v=vs.85%29.aspx
              var supportActiveX;
              try {
                  /* global ActiveXObject:true */
                  supportActiveX = !!new ActiveXObject( "Microsoft.XMLHTTP" );
              } catch( e ) {
                  supportActiveX = false;
              }
  
              if ( supportActiveX ) {
                  if ( window.XMLHttpRequest ) {
                      $.createAjaxRequest = function( local ) {
                          if ( local ) {
                              return new ActiveXObject( "Microsoft.XMLHTTP" );
                          }
                          return new XMLHttpRequest();
                      };
                  } else {
                      $.createAjaxRequest = function() {
                          return new ActiveXObject( "Microsoft.XMLHTTP" );
                      };
                  }
              } else if ( window.XMLHttpRequest ) {
                  $.createAjaxRequest = function() {
                      return new XMLHttpRequest();
                  };
              } else {
                  throw new Error( "Browser doesn't support XMLHttpRequest." );
              }
              return $.createAjaxRequest( local );
          }
docs: Create an XHR object
  @private
  @param {type} [local] If set to true, the XHR will be file: protocol
  compatible if possible (but may raise a warning in the browser).
  @returns {XMLHttpRequest}