var popWin = null    // use this when referring to pop-up window
		var winCount = 0
		var winName = "popWin"
		function openPopWin(winURL, winWidth, winHeight, winFeatures, winLeft, winTop){
		  var d_winLeft = 200  // default, pixels from screen left to window left
		  var d_winTop = 200   // default, pixels from screen top to window top
		  winName = "popWin" + winCount++ //unique name for each pop-up window
		  //closePopWin()           // close any previously opened pop-up window
		  if (openPopWin.arguments.length >= 4)  // any additional features? 
		    winFeatures = "," + winFeatures
		  else 
		    winFeatures = "" 
		  if (openPopWin.arguments.length == 6)  // location specified
		    winFeatures += getLocation(winWidth, winHeight, winLeft, winTop)
		  else
		    winFeatures += getLocation(winWidth, winHeight, d_winLeft, d_winTop)
		  popWin = window.open(winURL, winName, "width=" + winWidth 
		           + ",height=" + winHeight + winFeatures)
		  }
		function closePopWin(){    // close pop-up window if it is open 
		  if (navigator.appName != "Microsoft Internet Explorer" 
		      || parseInt(navigator.appVersion) >=4) //do not close if early IE
		    if(popWin != null) if(!popWin.closed) popWin.close() 
		  }
		function getLocation(winWidth, winHeight, winLeft, winTop){
		  return ""
		  }

  function getLocation(winWidth, winHeight, winLeft, winTop){
		  var winLocation = ""
		  if (winLeft < 0)
		    winLeft = screen.width - winWidth + winLeft
		  if (winTop < 0)
		    winTop = screen.height - winHeight + winTop
		  if (winTop == "cen")
		    winTop = (screen.height - winHeight)/2 - 20
		  if (winLeft == "cen")
		    winLeft = (screen.width - winWidth)/2
		  if (winLeft>0 & winTop>0)
		    winLocation =  ",screenX=" + winLeft + ",left=" + winLeft	
		                + ",screenY=" + winTop + ",top=" + winTop
		  else
		    winLocation = ""
		  return winLocation
		  }