Liftweb dynamic input field creation directly from RequestVar and SessionVar

LiftAjaxField.scala

object SessionSettings {
  object requestVar = net.liftweb.http.RequestVar[String]("")
  object sessionVar = net.liftweb.http.SessionVar[String]("")

  private def ajaxText[T <: AnyVar[String, _]](id: String, placeholder: String, field: T, validate: String => Boolean) = {
    def customSet(str: String): JsCmd = {
      if (validate(str)) {
        field.set(str)
        Noop
      } else {
        // do validation alert on input id
        Noop
      }
    }
    SHtml.ajaxText(field.get, customSet(_), "id" -> id, "placeholder" -> placeholder)
  }

  def render = "#sessionVar" #> ajaxText("sessvar", "this is per session, must be more than 5 chars", sessionVar, _.trim.length > 5) &
    "#requestVar" #> ajaxText("reqvar", "this is per request, must be less than 5 chars", requestVar, _.trim.length < 5) &
}