: {
        type: String,
        value: 'off'
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `autofocus` property.
       */
      autofocus: {
        type: Boolean
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `inputmode` property.
       */
      inputmode: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `minlength` property.
       */
      minlength: {
        type: Number
      },

      /**
      