Event Handler (Onkeyup and OnkeyDown)

Hello. For me to explain I am going to give you an example. I am working in a HTML text file. I am trying to create a way to highlight each line in the file with a highlighted box using the up and down error on the keyboard. A similar action is in a drop down box. In a drop down box the first option is highlighted. To highlight the other options you can use your mouse or up and down error on keyboard. Using JavaScript I would use Onkeydown/Onkeyup event handlers, correct? There is an example posted on ActiveWidgets found here...http://www.activewidgets.com/. By going to the link and clicking inside the table on the page; a cell becomes highlighted. Once highlighted you can move the highligted line up and down using the up and down error on the keyboard. I hope I am clear. Thank you in advance for your help.