One way can be by checking if window.parent[0].top.document
exists.
If you don't get an error when querying this object assume it's in the same domain, otherwise assume it's in different domains.
try {
if ( window.parent[0].top.document )
// Chrome & Firefox (same domain)
var origins = location.ancestorOrigins||{};
} catch(err) {
// Firefox (different domains CORS policy)
var origins = {"0":"*","length":1};
};
console.log(origins);
if ( !origins.length || origins[ origins.length -1 ] == location.origin ) {
// same domain
} else {
// different domains
var message = "Hellow Word!!";
window.parent.postMessage( message, origins[ origins.length -1 ] );
};