I am creating a web app that acts similar to a powerpoint presentation. I am using the mouse keys for navigation; left-click=forward, right-click = back. Problem is, right-click is always displaying a menu, I have searched past threads and 'return false;' is not doing it. it still appears in the next page. It will be run on win XP and IE 6.0.

Current (non working) code:
function mouseDown(e) {
var clickType = 1;
clickType = event.button;
if (clickType == 1){
parent.mainFrame.location = nav.front.value;
return true;
}
else {
parent.mainFrame.location = nav.back.value;
return false;
}
}
document.onmousedown = mouseDown;