JQuery validation : How to check items in multiple select

I have a form using JQuery validation plugin.

<label>
    <input name="Distribution[]" type="checkbox" id="dist_europe" class="required minlength:1" value="Europe" />  Europe 
</label>

<select name="Europe[]" size="5" multiple id="Europe">
   <option value='Albania'>Albania</option>
   <option value='Andorra'>Andorra</option>
   <option value='Austria'>Austria</option>
</select>

I need to do 'conditional' validation. eg. If checkbox is selected, make sure at least one item in 'select option is selected'.

 $(document).ready(function(){
     $("#commentForm").validate({
      rules: {
              Europe: {
                required: "#dist_europe:checked",
                minlength: 1
              }  
      },
      messages: {
        Europe: "Please select at least 1 country"
      }
     }
})

The issue I am facing now is :

1. I am able to detect that the checkbox is selected.
2. However, I am not able to check the 'select' array, Europe[]
3. If I remove the array, and name it Europe, I will be able to detect that at least one item is selected. But, doing that will mean the backend PHP scri开发者_StackOverflow中文版pt will not be able to process the multiple select in the array.

How do I work around this? Thanks

When using a name like name="Europe[]", you'll need to use a string for your identifier (the identifier is the name, not the id of the element) in rules and messages, like this:

$(document).ready(function(){
     $("#commentForm").validate({
      rules: {
        'Europe[]': {
                required: "#dist_europe:checked",
                minlength: 1
              }  
      },
      messages: {
        'Europe[]': "Please select at least 1 country"
      },
     debug: true
    });
});

You can test it out here.