window.opener always returns null

I'm creating a FF extension that needs to detect whether a window was opened via javascript with the window.open() command. I've tried many different ways: window.opener, parent.window.opener, this.opener, etc. and it always returns null. I was also trying it using the code editor here:

Re: window.opener always returns null

On 9/5/13 10:41 PM, digitalc...@gmail.com wrote: I'm creating a FF extension that needs to detect whether a window was opened via javascript with the window.open() command. Generally, testing .opener on the relevant window will work. However note that pages can explicitly null this out to