Reaction time to provide response

Hello there,
I'm looking to create a brief implicit associations test using Qualtrics, which as a newbie to HTML/Java is proving to be rather difficult.
What I need to be able to do is record the length of time it takes a participant to click a keyboard key after a stimulus has been presented (eg. a word appears on screen - they click "e" or "i" - Qualtrics logs that response time and goes on to the next question.
If anyone could give some advice as to where to begin with this it would be very much appreciated. At the moment I don't even know if it's HTML or Java I will need. Or if someone has created an IAT already I could copy, I would be eternally grateful!
Cheers!
Nick