How to record keypress

Hi!
I'm trying to figure out a way to have participants press the spacebar in response to certain stimuli and record whether or not they pressed it (saving it so it is in the output would be best), but I also do not want the page to move forward if they do press it (my pages automatically advance right now, and I want it to stay like that). Is there any way to do this, or, alternatively, a way to add a custom button to the screen that they can click instead of the spacebar? (Spacebar method is preferred, but I'll take any suggestions)
Thank you!