Show select when checkbox is checked and validate select as required

Question

I have added new fields in the configuration file for my form, like this:

<?xml version="1.0" encoding="utf-8"?>
<form>
    <fieldset>
        <field name="yes" type="checkbox" label="Answer yes" />
        <field name="options" type="list" label="Type" description="">
          <option value="" selected="selected">default</option>
          <option value="Option1">Option1</option>
          <option value="Opcion2">Option2</option>
        </field>
    </fieldset>
</form>

In the view, I show the fields:

<div class="control-group">
    <div class="control-label">
       <?php echo $this->form->getLabel('yes'); ?>
    </div>
    <div class="controls">
       <?php echo $this->form->getInput('yes'); ?>
    </div>
</div>
<div class="control-group" id="div_options" style="display: none;">
    <div class="control-label">
         <?php echo $this->form->getLabel('options'); ?>
    </div>
    <div class="controls">
         <?php echo $this->form->getInput('options'); ?></div>
    </div>
</div>

And with Javascript (jQuery), I have set the condition that when the checkbox is checked, I show the select with options. But I need to validate with Joomla that just in case the checkbox is checked, the selection is mandatory and the user must select an option.

if (jQuery('#jform_yes').is(':checked')) {
    jQuery("#div_copciones").show();
    jQuery("#jform_options_chzn").attr('required', true);
    jQuery("#jform_options_chzn").addClass('validate-options');
} 

jQuery('#jform_yes').on('change', function(){
    if (this.checked) {
        jQuery("#div_opciones").show();
        jQuery("#jform_options_chzn").attr('required', true);
        jQuery("#jform_options_chzn").addClass('validate-options');

    } else {
        jQuery('#jform_yes').val(0);
        jQuery("#jform_options_chzn").attr('required', false);
        jQuery("#div_options").hide();
    }
});

How can I validate that the user chooses an option in the select before sending the form? Is my process correct? Is there any better way to do it? Thanks!