/* xMenu1 Object Prototype

  Parameters:
    triggerId   - id string of trigger element.
    menuId      - id string of menu.
    mouseMargin - integer margin around menu;
                  when mouse is outside this margin the menu is hid.
    openEvent   - string name of event on which to open menu ('click', 'mouseover', etc).
*/

function xMenu1(triggerId, menuId, mouseMargin, openEvent)
{
  var isOpen = false;
  var trg = xGetElementById(triggerId);
  var mnu = xGetElementById(menuId);
  if (trg && mnu) {
    xAddEventListener(trg, openEvent, onOpen, false);
  }
  function onOpen()
  {
    if (!isOpen) {
      xMoveTo(mnu, xPageX(trg) - xWidth(mnu) + xWidth(trg), xPageY(trg) + xHeight(trg));
      xShow(mnu);
      xAddEventListener(document, 'mousemove', onMousemove, false);
      isOpen = true;
    }
  }
  function onMousemove(ev)
  {
    var e = new xEvent(ev);
    if (!xHasPoint(mnu, e.pageX, e.pageY, -mouseMargin) &&
        !xHasPoint(trg, e.pageX, e.pageY, -mouseMargin))
    {
      xHide(mnu);
      xRemoveEventListener(document, 'mousemove', onMousemove, false);
      isOpen = false;
    }
  }
} // end xMenu1