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

if ( window.location !== window.parent.location ) 
{
      // The page is in an iframe   
} 
else 
{     
      // The page is not in an iframe   
}