Issue communication with postMessage from parent to child iFrame

问题

I'm having an issue communicating from my parent window to the child iFrame. But in the other side, everything works perfectly. Here is how I get the chil iFrame object in order to fire the postMessage function:

var iFrame = document.getElementById('Frame').contentWindow;

When I print it int he console, I get the following:

Window {parent: Window, opener: null, top: Window, length: 0, frames: Window…}

When I proceed to the postMessage function as follows:

iFrame.postMessage("message", "http://contoso.com");

It shows me an error when loading the page: iFrame.postMessage is not a function. When I execute the postMessage in console, I get an undefined

What am I doing wrong ?

回答1:

try this

var iFrame = document.getElementById('Frame');
iFrame.contentWindow.postMessage("message", "http://contoso.com");

I had this problem too. I found solution from this website https://www.viget.com/articles/using-javascript-postmessage-to-talk-to-iframes

回答2:

Below code also works.

$('#id')[0].contentWindow.postMessage("hello world",targetOrigin);

There is a difference between jQuery selector and document.getElementById.

Document.getElementByID returns HTML DOM object.
jQuery selector returns jQuery object.

For more information please find below link. document.getElementById vs jQuery $()

来源：https://stackoverflow.com/questions/40991114/issue-communication-with-postmessage-from-parent-to-child-iframe