// www.lacertagames.com  by Dave Carlson
// get screen size for display

var xSize=screen.availWidth-250; 
var ySize=Math.round(xSize/4.5);

// operate drop down menu

var closeTimer	= 0;
var ddMenuItem	= 0;

function menuOpen(id)
  {	
  menuCloseTimerCancel();
  if(ddMenuItem) ddMenuItem.style.visibility = 'hidden';
  ddMenuItem = document.getElementById(id);
  ddMenuItem.style.visibility = 'visible';
  }

function menuClose()
  {
  if(ddMenuItem) ddMenuItem.style.visibility = 'hidden';
  }

function menuCloseTimer()
  {
  closeTimer = window.setTimeout(menuClose, 250);
  }

function menuCloseTimerCancel()
  {
  if(closeTimer)
    {
    window.clearTimeout(closeTimer);
    closeTimer = null;
    }
  }