✓ POST Request by Fetch

post.php

<?php
header( 'Access-Control-Allow-Origin: *' );

print_r( $_POST );

postByFetch.js

fetch( 'post.php',
{
	method: 'POST',
	headers: { 'Content-Type' : 'application/x-www-form-urlencoded' },
	body: 'data1=Hello World!&data2=Hello Universe!'
})
.then( response => response.text() )
.then( data => console.log( data ) )
.catch( error => console.error( 'Error:', error ) );