Customizing interface of multiselect in magento

Question

My multi select list is very large, it is difficult to find out which options are selected, I want to change it into some thing like following, is it possible? It can be any where, but currently I have a custom "customer_address" attribute type "multiselect",

I am creating my attribute like this my sql script,

    <?php

$installer = $this;

$installer->startSetup();

$installer->addAttribute('customer_address', 'additional_managers', array(
    'label' => 'Additional Store/Site Managers',
    'visible' => true,
    'required' => false,
    'type' => 'varchar',
    'input' => 'multiselect',
    'source' => 'abc_districtmanager/address_attribute_source_districtmanager',
    'onclick' => 'getSelectValues(this)',
    'user_defined' => 1,
    'position' => 100
));

$used_in_forms = array(
     'adminhtml_customer_address',
     'customer_address_edit',
     'customer_register_address'
    );

$attribute = Mage::getSingleton('eav/config')->getAttribute('customer_address', 'additional_managers');
$attribute->setData('used_in_forms', $used_in_forms); 
$attribute->save();

$installer->endSetup();

Answer 1

I got my purpose with a slight changed interface by using "Chosen" jquery.

Download Chosen Jquery chosen.jquery.js and chosen.css, place these files in your design, Add them to you module in respected .xml file, in head like

     <reference name="head">
        <!--            Adding js and css to use "chosen" instead of "select" for "multiselect" input types-->
        <action method="addItem">
            <type>skin_js</type>
            <name>js/chosen.jquery.js</name>
        </action>
        <action method="addItem">
            <type>skin_css</type>
            <name>css/chosen.css</name>
        </action>
    </reference>

be careful about path of files, after this, in your respected view (.phtml) use Chosen

<script type="text/javascript">

jQuery(document).ready(function ($) {
    $(".myClass").chosen();
});

This will change interface of elements having class "myClass", output might like this

Answer 2

you can achieve this functionality by below code

<select onchange="getSelectValues(this)"></select>



    function getSelectValues(select) {

          var options = select && select.options;
          var opt;

          for (var i=0, iLen=options.length; i<iLen; i++) {
            opt = options[i];

            if (opt.selected) {
               opttext +=opt.text+'<br />';
            }
          }
          document.getElementById('showdiv').innerHtml=opttext;
        }

doing with prototype

$("_itemNaNadditional_managers").invoke('observe', 'change', function() {

    var options = $("_itemNaNadditional_managers").options;
              var opt;

              for (var i=0, iLen=options.length; i<iLen; i++) {
                opt = options[i];

                if (opt.selected) {
                   opttext +=opt.text+'<br />';
                }
              }
              document.getElementById('showdiv').innerHtml=opttext;

});