// This function is designed to be a wrapper for existing event-
// handlers in order to avoid rewriting existing functions. It prevents
// the default event-handler from being called, and returns it's second
// argument. (It will for example prevent a link from being followed
// when clicked.) Since it returns the second argument it becomes 
// transparent to it's caller.
function preventDefault(evt, forward) {
  // Internet explorer:
  if (window.event) {
    evt.returnValue = false;
  }

  // Standard browsers:
  else if (evt.preventDefault) {
    evt.preventDefault();
  }

  return forward;
}