I want to adjust (center) the source webpage in iframes.. Also knowing how to adjust up and down, if possible, would be nice. If no solution is availble, is there any other option? I was thinknig like using the object element be used instead of iframe tag for this
The iFrame is another page, you'd apply margin:auto to the content that goes in there. If you have no control over the content, I doubt there's much you can do. Cross-frame security policies prevent you from doing anything to an iFrame'ed page, unless it exists on the same domain.