How do I postMessage to iframe?

Code used in this page

  1. window.onload = function () {
  2. var iframeWin = document. getElementById( “da-iframe” ). contentWindow,
  3. form = document. getElementById( “the-form” ),
  4. myMessage = document. getElementById( “my-message” );
  5. myMessage. select();
  6. form.onsubmit = function () {

What is postMessage in JavaScript?

postMessage() method safely enables cross-origin communication between Window objects; e.g., between a page and a pop-up that it spawned, or between a page and an iframe embedded within it.

Can JavaScript interact with iframe?

On this page, two iframes interact with each other using JavaScript. First we show how one iframe can get references to the other iframe and the document inside it. Then we provide an example which demonstrates one iframe accessing and modifying the other’s properties, objects, and content.

How do I transfer data from iframe to parent?

Send data from an iframe to its parent window

  1. const message = JSON. stringify({
  2. date: Date. now(),
  3. window. parent. postMessage(message, ‘*’);

What is the difference between SendMessage and postMessage?

postMessage: Sends a message in the message queue associated with the thread and returns without waiting for the thread to process that messaage. SendMessage: calls the window procedure for the specified window and does not return until the window procedure has processed the message.

Is postMessage safe?

postMessage is generally considered very secure as long as the programmer is careful to check the origin and source of an arriving message. Acting on a message without verifying its source opens a vector for cross-site scripting attacks.

How do you communicate between two iframes?

Communicating directly between iframes is also possible by combining window. parent with target as defined above. In conclusion, the postMessage method is a more dynamic alternative to the single DOM, better suited if you load multiple pages in one iframe, but not always easier and it still requires the use of the DOM.

How do you communicate with iframe and parent site?

All you have to do is first dispatch an event from the iframe to the parent that notifies the parent that the iframe is loaded (essentially a “ready message”). The parent will be listening for messages and if it receives the “ready message” event, it can then reply to the iframe with whatever message you want to send.

Can iframe access parent document?

When a page is running inside of an iframe, the parent object is different than the window object. You can still access parent from within an iframe even though you can’t access anything useful on it. This code will never cause an error even when crossing origins.

What is the difference between SendMessage and PostMessage in MFC?