cross site iframe postMessage from child to parent

Question

I found this samplefrom SO while browsing for my problem, but I want to know exactly how to use it in my scenario. I have an iframe which is from another domain, and I want

Answer 1

You need to set targetOrigin when using postMessage.

Then on the host page.

function addAnEventListener(obj,evt,func){
    if ('addEventListener' in obj){
        obj.addEventListener(evt,func, false);
    } else if ('attachEvent' in obj){//IE
        obj.attachEvent('on'+evt,func);
    }
}

function iFrameListener(event){
     secondPageValue = event.data;
}

var secondPageValue='';

addAnEventListener(window,'message',iFrameListener);