How to send a POST request from WordPress admin Dashboard

How to send a POST request from WordPress admin Dashboard – JS

(function(){

	var request = wp.ajax.post('custom_action', {param1: 'uppercase this string pls'});

	// on success
	request.done( function ( res ) {
		console.log( res );
	});

	// on fail
	request.fail( function ( res ) {
		console.log( res );
	});
})();

PHP

<?php
// this function will be called when the request is triggered
function listen_for_ajax() {

	if ( ! empty( $_POST['param1'] ) ) {

		$upercased = strtoupper( $_POST['param1']);

		wp_send_json_success( $upercased );
	}

	wp_send_json_error('no param');
}


// hook this function for admin actions
add_action( "wp_ajax_custom_action", "listen_for_ajax");
// for public actions use `nopriv_` before action name
add_action( "wp_ajax_nopriv_custom_action", "listen_for_ajax");