✓ POST Request by Fetch

post.php

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

$received = file_get_contents( 'php://input' );

echo $received;

// Ref: https://www.php.net/manual/en/reserved.variables.post.php#125651

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 ) );

// Send data as json
fetch( 'post.php',
{
	method: 'POST',
	headers: { 'Content-Type' : 'application/json' },
	body: JSON.stringify( todo )
})
.then( response => response.text() )
.then( data => console.log( data ) )
.catch( error => console.error( 'Error:', error ) );