var mywindow = window.open("apage.html");
var mydocument = mywindow.document;
When I tried this I got an error, but I don't think the error occurred because the browser blocked the popup window. I found an example similar to this on w3schools home page and it worked fine. In this example too, there was no error when I had only the window.open command, but the error occurred after I added the second line. What I think is that there is an access error. The above open statement actually looks more like this:
apage.html is not my page, but someone else's. Is there some rule that you can't get access to the document object of a window displaying someone else's page?