Grails Ajax选择

I'm trying to implement a select using Ajax, following this tutorial: https://halleysweblog.wordpress.com/2014/02/19/ajax-driven-selects-in-grails/

But nothing works. Follows the code :

selectChain.gsp

<!DOCTYPE html>
<html>
<head>
    <meta name="layout" content="main"/>
    <title>Cadastro de Cidade</title>
    <g:javascript library="jquery" />
</head>

<body>

<div>
    <div>
        <g:select name="country.id" from="${teste}" optionKey="id"
                  optionValue="name" noSelection="['':'Select Country']"
                  onchange="${remoteFunction (controller: 'country',
                          action: 'findCityForCountry',
                          params: '"country=" + this.value',
                          update: 'citySelection'
                  )}" />
    </div>
    <div id="citySelection">
        <select>
            <option>Select City</option>
        </select>
    </div>
</div>

</body>
</html>

Controller:

package projetoaep

class CountryController {

    def index() {
        render(view: "/country/selectChain")
    }

    /*
     * Finding the cities for a specific country
     */
    def findCityForCountry() {
        def country=Country.get(params.country)
        render(template: 'citySelection', model:  [cities: country.cities])
    }

    /*
     * For the view
     */
    def selectChain() {
        [teste : Country.list()]
    }
}

citySelection.gsp

<!-- This template renders a drop down after a country is selected -->

<g:select name="city.id" from="${cities}" optionValue="name"
          optionKey="id"/>