javascript - Cross domain iframe issue

Question

For say i have a Site called example.com on which iframe is embedded of domain iframe.net, now i want to read the content of iframe and pass some parameter to display a textual message. Like Hi with username.

Now the problem is this able not able to make connection between the two , even am not able to get the innerHTML of iframe i used following approach

document.getElementById('myframe').contentWindow.document.body.innerHTML;

It throws error "Permission denied to access property"

Do anyone know how to read and write in cross domain platform

Answer 1

If you don't have control over the framed site, you cannot circumvent the cross-domain policy.

If you have control over both sites, you can use the postMessage method to transfer data across different domains. A very basic example:

// framed.htm:
window.onmessage = function(event) {
    event.source.postMessage(document.body.innerHTML, event.origin);
};

// Main page:
window.onmessage = function(event) {
    alert(event.data);
};

// Trigger:
// <iframe id="myframe" src="framed.htm"></iframe>
document.getElementById('myframe').contentWindow.postMessage('','*');