Make a DIV not be shown outside it's container

Question

I\'m making a very basic animation with JQuery. Basically what I have is a DIV in the size of 60% width, 80% height and it contains a manual. My goal is that when you go through

Answer 1

basically this is done by adding CSS

overflow: hidden;

to the enclosing container, but without seeing the code over here, getting help is hard.