docs: function($modal, onOk, onCancel) {
          var that = this;
          var $btnOk = $modal.querySelector('.btn-ok');
          var $btnCancel = $modal.querySelector('.btn-cancel');
  
          // toasts delay hide
          if (commonUse.hasClass($modal, 'toasts')) {
            setTimeout(function() {
              // if toasts has been removed
              if (document.getElementById($modal.id) === null) return;
              that.close($modal, onOk);
            }, that.defaults.time);
          }
          // click ok button
          if ($btnOk) {
            commonUse.addEvent($btnOk, 'click', function() {
              that.close($modal, onOk);
            });
          }
          // click cancel button
          if ($btnCancel) {
            commonUse.addEvent($btnCancel, 'click', function() {
              that.close($modal, onCancel);
            });
          }
        }