ajaxOnSubmit function to use in CssSelectorTransforms to add ajaxSubmit behavior to both button and input submit elements.

FormHelpers.scala

package net.liftweb.http

import scala.xml._

import net.liftweb.common._
import js._
import net.liftweb.util.Helpers._

object FormHelpers {
  /**
   * Add appropriate attributes to an input type="submit" or button
   * element to make it submit an ajaxForm correctly and return a JsCmd
   * to the client.
   *
   * Example:
   *
   *  <pre>"type=submit" #> ajaxOnSubmit(() => Alert("Done!"))</pre>
   */
  def ajaxOnSubmit(func: () => JsCmd): (NodeSeq)=>NodeSeq = {
    import S._

    val fgSnap = S._formGroup.get

    (in: NodeSeq) => S._formGroup.doWith(fgSnap) {
      def runNodes(ns: NodeSeq): NodeSeq = {
        def addAttributes(elem: Elem, name: String) = {
          val clickJs = "liftAjax.lift_uriSuffix = '" + name + "=_'; return true;"

          elem % ("name" -> name) % ("onclick" -> clickJs)
        }

        ns.flatMap {
          case Group(nodes) => runNodes(nodes)

          case e: Elem if (e.label == "button") ||
                          (e.label == "input" && e.attribute("type").map(_.text) == Some("submit")) =>
            _formGroup.is match {
              case Empty =>
                formGroup(1)(fmapFunc(func)(addAttributes(e, _)))
              case _ => fmapFunc(func)(addAttributes(e, _))
            }
        }
      }

      runNodes(in)
    }
  }
}