Select multiple element not empty validation engine without required

Question

I need to do validation that at least one element is selected. This element was filled dynamically and I need to validate if that I have at least one option element selected, using validation Engine.

Here fill the select option item

jQuery("#bt_add").click(function(){
    storeUsedGroups[attr_group.val()] = true;

    jQuery("#atributo_id").append('<option value='+attr_name.val() + 
        ' groupid='+attr_group.val()+'>' + attr_group.text() + 
        ' : ' + attr_name.text()+'</option>'
    );
});

and validate with required, but for submit form need select the options inserted.

<select name="atributo_id[]" id="atributo_id" multiple="multiple" class="validate[required]">
    <option value="5" groupid="1">Color : Azul</option>
</select>

I just need to validate non-empty the element.

Answer 1

UPDATE: If I understand you correctly you want to apply required rule only if select element was populated with options.

You can do that with custom function call. Change your select's class to

<select name="atributo_id[]" 
        id="atributo_id" 
        multiple="multiple" 
        class="validate[funcCall[ifSelectNotEmpty]]">

Now the function

function ifSelectNotEmpty(field, rules, i, options){
  if ($(field).find("option").length > 0 && 
      $(field).find("option:selected").length == 0) {
     // this allows the use of i18 for the error msgs
     return "* This field is required";
  }
}

It supposed to be working, but it won't because jquery.validationEngine.js crashes on line 707 (IMHO it's a bug). So you need to change line 707 from

if(!required && && !(field.val()) && field.val().length < 1) options.isError = false;

to

if(!required && !field && !(field.val()) && field.val().length < 1) options.isError = false;
                ^^^^^^

Original answer If you want to check if any of options has been selected you can do it like this

if (!$("#atributo_id option:selected").val()) {
    alert("Nothing has been selected");
}

or

if (!$("#atributo_id option:selected").length) {
    alert("Nothing has been selected");
}

jsFiddle