Web Messaging Demo: Telling the parent document

In this document, we are:

• Opening a new window.
• Adding a message event listener and handler.
• Once that message event is fired, we will use our event handler to invoke window.postMessage() (and using setTimeout to delay the message posting).

In the document of our new window, we are:

• Setting up an event listener that will post a message to this window when that document loads.
• Adding a message event listener and handler to listen for message events posted from this document.

Open the window