iframe postMessage tests

by s_light

HTML

<button onclick="ping();">
Ping
</button>

<div>
    <h2>
    Log entries:
    </h2>
    <ul id="log">
    
    </ul>
</div>

CSS

body {
    background-color:black;
    color:orange;
}

JavaScript

function ping() {
    window.top.postMessage('PING');
    add_log('send ping to top level window...');
}


window.addEventListener ("message", (event) => {
    console.log('jsfiddle', event);
});
















function add_log(message) {
	const log = document.querySelector('#log');
    const el = document.createElement('li');
    const now = new Date();
    el.innerText = `${now.toISOString()} - ${message}`;
    log.append(el);
    console.log(message);
}