Is there a way to access an iframe's window object from the canvas in FBJS (facebook)

var myIframe = document.getElementById('myIframeId');

// could retrieve window or document depending on the browser
// (if FBJS allows it!?)
var myIframeWin = myIframe.contentWindow || myIframe.contentDocument;

if( !myIframeWin.document ) { //we've found the document
    myIframeWin = myIframeWin.getParentNode(); //FBJS version of parentNode
}