.postMessage() Example - Sender

by Gerald Gillespie

HTML

<textarea id="text"></textarea>
<button id="btn">Send Message</button>

<!-- uncomment for iframe example -->
<iframe width="100%" height="400" src="https://jsfiddle.net/gillyspy/8ybn6stk/2/show" frameborder="0" id="child"></iframe>

JavaScript

//const childWindow = window.open("https://jsfiddle.net/ozzan/wmxf9fs2/show", "_blank");
 //uncomment for iframe example

var btn = document.getElementById("btn"),
    text = document.getElementById("text");

btn.addEventListener("click", function() {
    sendMessage(text.value);
    text.value = "";
});

function sendMessage(message) {
     const childWindow = document.getElementById("child");// .contentWindow;
   //  console.log('cw',childWindow);
    if (!message || !message.length) return;
    childWindow.contentWindow.postMessage(JSON.stringify({
        message: message,
        time: new Date()
    }), "https://jsfiddle.net/");
    console.log("sent");
}