I need to open in the background of my page ( something like a iframe) a webpage that redirects to another webpage.
So A is my main page and I want to open page B, that redirects to page C. So the page B and page C should be opened in the background, without user knowing.
If I use iframe, my current page(A) gets redirected too to C and I don't want this to happen!
If B redirects to C with a simple Location: ... header, your solution should work fine.
If B redirects to C with a script such as top.location = ... theres not much you can do about it, sorry.
It's also possible that C contains a "frame buster" which breaks out of iframes.
In other words, you're out of luck unless you go for a very complex solution such as this frame buster buster.