Hinaloe

This plugin allow your site’s comment form makes ajax — non move/reload when user (including both subscriber, normal viewer, and admins too) post comment!
Most themes supports this plugin, but if your theme’s <code>class_form</code> have not <code>comment-form</code>, this plugin non supported.
And this plugin only can use for Pure WordPress Comment form. 
so, its not able to be used with like Jetpack comment form and other original/outside comment system/form.
Feature
<ul>
<li>post comment with ajax</li>
<li>Lite — this plugin only using a little of jQuery feature to modify DOM, and very tiny js & PHP code.</li>
</ul>
Require
You have to install <a href="https://wordpress.org/plugins/rest-api/" rel="ugc">WP REST API v2</a> to use this plugin if your site is running on WP 4.4-4.6.

ajax Post Comment

Post comment form on frontend tobe ajax using WP REST API Version.2

Austin

Fulvio Notarstefano

This plugin extends the <a href="https://wordpress.org/plugins/json-rest-api/" rel="ugc">WordPress JSON REST API</a> with new routes for WordPress registered menus
The new routes available will be:
<ul>
<li><code>/menus</code> list of every registered menu.</li>
<li><code>/menus/<id></code> data for a specific menu.</li>
<li><code>/menu-locations</code> list of all registered theme locations.</li>
<li><code>/menu-locations/<location></code> data for menu in specified menu in theme location.</li>
</ul>
Currently, the <code>menu-locations/<location></code> route for individual menus will return a tree with full menu hierarchy, with correct menu item order and listing children for each menu item. The <code>menus/<id></code> route will output menu details and a flat array of menu items. Item order or if each item has a parent will be indicated in each item attributes, but this route won’t output items as a tree.
You can alter the data arrangement of each individual menu items and children using the filter hook <code>json_menus_format_menu_item</code>.
An important note on WP API V2:
In V1 the routes are located by default at <code>wp-json/menus/</code> etc.
In V2 the routes by default are at <code>wp-json/wp-api-menus/v2/</code> (e.g. <code>wp-json/wp-api-menus/v2/menus/</code>, etc.) since V2 encourages prefixing and version namespacing.

WP API Menus

It Does!

Extends WordPress WP REST API with new routes pointing to WordPress menus.

ajax Post Comment vs WP API Menus