JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bulk_action">
<select name="action_top">
       <option value="" selected style="visibility:hidden; display:none">Bulk Action</option>
        <option value="Delete" class="bulk_action_delete">Delete</option>
        <option value="Set Under" class="bulk_action_target">Set under group :</option>
        <option value="Remove Under" class="bulk_action_target">Remove under group :</option>
 </select>

<select name="group_tag_top" class="normal_select group_tag_dynamic" id="group_tag">
    <option selected value="0" style="visibility:hidden; display:none">-- Select --</option>
    <option value="1">Fashion</option>
    <option value="1">Sport</option>
    <option value="1">Mobile</option>
</select>
</div>

JavaScript

var $x = jQuery.noConflict();

$x(document).ready(function() {
    $x(".group_tag_dynamic").hide(); //default
    $x("select[name=action_top]").change(function() {
        var selectedOption = $x(this).find('option:selected');
        if(selectedOption.hasClass('bulk_action_target'))
            $x(".group_tag_dynamic").show('slow');
        else if(selectedOption.hasClass('bulk_action_delete'))
            $x(".group_tag_dynamic").hide('slow');
    });
});