Site sizing question

I have a movieclip which will load in the .php file I want, which then in turn loads in the back end for the website(e commerce). Now if that works how I think it should, when it loads let’s say the content is to big for the clip. Instead of making the clip have a scrollbar, how do I make it so the site extends in height to accommodate the new size? If anyone is familiar with loading backends into a flash site I’d love to chat and get to know more about this.