Validate chosen plugin dropdown using jquery validate plugin

Question

I made dropdown using chosen plugin and want to validate uisng jquery validate_init.js plugin but i cant validate

I give both rules and messages in validate.js file but cant work for me,find my code below

<select class="chzn-select form-control input-crtl input-drp" id="cus_record" name="customer_name" placeholder="Select Customer" width="391px">
  <option value="0">Select Customer</option>
  <?php foreach($customers_records as $key=>$value) { ?>
    <option <?php if(set_value('customer_name',$this->form_data->customer_id) == $value->id) { echo "selected";} ?> value="<?php echo $value->id; ?>"><?php echo $value->first_name." ".$value->last_name."(".$value->email.")"; ?></option>
   <?php } ?>
 </select>

$("#advertisement_form1").validate({
  rules: {
    customer_name: {
      required: true,
    }
  }
  customer_name: {
    required: 'Customer name field is required.',
  },
})