how to use get_field_name in external ajax handler

Question

I am loading new form fields from Ajax when I click on radio button in my custom widget. In Ajax callback handler, I need to use get_field_name and get_field_id widget class methods. get_field_name method is return in WP_Widget class. So I try to get the instant of that class. But I unable to do that. So please someone help me how to use it in external class.

   function wp_ajax_suport(){

    add_action('wp_ajax_my_func', 'my_func');
    add_action('wp_ajax_nopriv_my_func', 'my_func');
    }    
    add_action( 'init', 'wp_ajax_suport' );

    function my_func(){

    <input type="text" name="<?php $this->get_field_name('name'); ?>">
    }

Answer 1

Why you want to use ajax for showing some fields on form in widget? Can't it be done using simple show hide using jquery. See below. Not tested , just to give insight.

HTML

<input type="radio" id="someradio" />
<div id="somediv" style="display:none;">
    <input type="text" name="<?php $this->get_field_name('name'); ?>">
</div>

Jquery

<script type="application/javascript">
    jQuery('#someradio').on('click',function(){
        jQuery('#somediv').toggle();
    });
</script>