JavaScript to detect if the parent frame is of the same origin?

Question

I'm looking for a cross-browser way to detect whether the parent frame is the same origin as my frame, preferably without printing warnings on the JavaScript error console.

The following seems to work but I'd like to avoid printing errors to the console (at least Safari and Chrome do when accessing location.href on the parent frame. Firefox throws an exception which can be caught):

function parentIsSameOrigin() {
    var result = true;
    try {
        result = window.parent.location.href !== undefined;
    } catch (e) {
        result = false;
    }
    return result;
}

Answer 1

Try this:

function parentIsSameOrigin()
{
    var result = true;
    if (window.parent)
    {
        result = Boolean
        (
            // more precise modifications needed here
            window.this.location.href.indexOf(window.parent.location.href) == 0
        );
    }
    return result;
}

Answer 2

I use this method to tell if an iframe contains local content,

but you can pass it window.top from the iframe just as well

function islocal(win){
var H=location.href,
    local= H.substring(0, H.indexOf(location.pathname));
    try{
        win=win.document;
        return win && win.URL && win.URL.indexOf(local)== 0;
    }
    catch(er){
        return false
    }
}

//test case alert(islocal(window.top))

Answer 3

I would do something like:

var sameOrigin;
try
{
    sameOrigin = window.parent.location.host == window.location.host;
}
catch (e)
{
    sameOrigin = false;
}
return sameOrigin;