Why does onclick event trigger when i use arrow keys to move between buttons

I have button navigation set up for four buttons so that the arrow keys will move between all buttons. Problem is that when i press the arrow key it moves to the next button as it should but it triggers the onClick event assigned to that next button. I want to be able to move between all buttons until I get to the one that i want and then trigger the onClick event for that button by pressing the space key. What am I missing here.