Text invisible when printing

I just thought of a feature that might be useful if it was implemented. I was working on a history paper, and had some notes on it for a later revision. I needed to print the current revision off to hand in, but didn't want the notes to be on there. Then it hit me: what if there was a way to select an amount of text, and make it only visible on the computer while editing. I know there are ways to take the text out and put it back in, but I was just thinking that would be a convenient feature.