grails: ajax powered validation [Update]

In a previous post, I outlined a method to perform textfield validation using jQuery. However a recent comment by Jan correctly pointed out a simpler method using grails' own ajax tag, <g:remoteField>.

So to implement this feature in a simpler way do the following,

Step 1: Import scriptaculous

<g:javascript library="scriptaculous"/>

Step 2: Code up the textfield and message div

<g:remoteField controller="member" action="validateUsername" paramName="username" name="username"

update="messageDiv" value="${fieldValue(bean:member,field:'username')}">

</g:remoteField>

<div id="messageDiv" style="color:blue"></div>

The message div will be populated with the ajax response, i.e. the uniqueness validation result.

Step 3: Code up the grails action

def validateUsername = {

        def message = ""

      def inUse = ["homer", "marge", "bart", "maggie", "lisa"]

      if (params.username)
      {
          if(inUse.contains(params.username))
          {
              message = "The username has already been taken. Please enter a different one"
          }
          else
          {
              message = "Username Ok !...."
          }
      }     

      render message

  }

Not much change here other than the response messages.

And that's it.