How to identify if a webpage is being loaded inside an iframe or directly into the browser window?

Question

I am writing an iframe based facebook app. Now I want to use the same html page to render the normal website as well as the canvas page within facebook. I want to know if I

Answer 1

I'm using this:

var isIframe = (self.frameElement && (self.frameElement+"").indexOf("HTMLIFrameElement") > -1);