(cross-domain) Call parent function from outside iframe is forbidden

Question

...but I do control part of the javascript inside the second domain (which integrates the iframe). So, what I need is some workaround my problem. We have example2.com (this one holds the iframe) and example.com (this one is the original, within the iframe). Inside the iframe the user clicks a button that executes parent.redirectUser() and although I have that function defined in example2.com it fails to execute because it points the function as forbidden to access from within the iframe. Considering I can control the javascript in example2.com, is there any other way to workaround this situation? Thank you very much for your help...

Answer 1

Yes, you can do it. You can use messages technique, send message from child(example2.com):

parent.postMessage("Ok", "example.com");

in parent(example.com) you must add the following code:

    //add eventlistener for message event
    if (window.addEventListener) {
        window.addEventListener("message", listener);
    } else {
        // IE8
        window.attachEvent("onmessage", listener);
    }
    function listener(event) {
//check the message trust or not?
        if (event.data == "Ok") {
//from parent you can call function, but function must be placed in global scope
            redirectUser();
        }
    }