Unhide content when user scrolls down

I was having to load content on demand with jquery, but I solved the problem with this post . But now what I need is to do the opposite ... when loading the new content, the content that was being displayed needs to be removed so that the page does not get so overloaded ... what happens is that I do not know how to do that when the user decides to go back, the script identifies this and reloads the previous content! How can I identify that the user is returning the content so I can reload it?