code: function isPotentiallyTabbableIOS(element) {
      var /** @type {?} */ nodeName = element.nodeName.toLowerCase();
      var /** @type {?} */ inputType = nodeName === 'input' && ((element)).type;
      return inputType === 'text'
          || inputType === 'password'
          || nodeName === 'select'
          || nodeName === 'textarea';
  }
docs: Checks whether the specified element is potentially tabbable on iOS
  @param {?} element
  @return {?}