Detect iFrame embedding in Javascript

Question

I have an application on which there is a specific page - call him Page A. Page A is sometimes a top-level page, but also sometimes embedded as an iframe inside page B. All pages come from the same server and there are no problems between domains.

I have a greasemonkey script that runs on page A. How does a greasemonkey script detect if page A is in an iframe context or not?

Answer 1

Looking at the frame length, it breaks at all if page A itself has frames (I know that this may not be the case for this particular instance). A more reliable and significant test will be:

if (window!=window.top) { /* I'm in a frame! */ } 

Answer 2

Predicate

 (window.parent.frames.length > 0) 

will tell you what you want.

Answer 3

 if (top === self) { not in a frame } else { in a frame } 

From How to determine if a webpage is loading inside an iframe or directly in a browser window?

Answer 4

As stated above, the decision does not work in IE8. In addition, checking window.parent.frames.length may cause cross-domain exclusion.

Instead, I was able to achieve this with var isInIFrame = top.location != self.location - it works in IE8 and does not cause cross-domain violation if you are not trying to read the contents of top.location .

Answer 5

Use window.frameElement and check if it is null and if its nodeName is "IFRAME".