I have a customized Create New Classified form and the input fields that should be required aren&#03

I have created a custom form to create new classifieds/edit classifieds using the do_shortcode to generate the input fields. A typical input field looks like this:

<div class="editfield">
<label for="title"><?php _e( 'Sale Price', $this->text_domain ); ?></label>
<?php echo do_shortcode('[ct_in id="_ct_text_4cfeb3eac6f1f" property="input"]'); ?>
</div>

The problem is...this should be a required field, and I can submit the form even if it is empty!

Is there something I need to add in the shortcode to make it required?

Thanks!

jc