code: function(iframe, params){
          // We can't use the following code in IE6
          // var form = document.createElement('form');
          // form.setAttribute('method', 'post');
          // form.setAttribute('enctype', 'multipart/form-data');
          // Because in this case file won't be attached to request
          var form = qq.toElement('<form method="post" enctype="multipart/form-data"></form>');
  
          var queryString = qq.obj2url(params, this._options.action);
  
          form.setAttribute('action', queryString);
          form.setAttribute('target', iframe.name);
          form.style.display = 'none';
          document.body.appendChild(form);
  
          return form;
      }
docs: Creates form, that will be submitted to iframe