title: How can we know when pop-up window url is loaded (window.open)?
body: <p>I need to change the URL of the page in the pop-up as soon as it completes loading ( I am  using window.open function call).
  Is there anyway I can find out when the page in pop-up has completed loading in the parent window? I cannot change anything in the page I am opening in pop-up, because it belongs to another website.</p>