var oneTimeWinName = "oneTimePop"
function openPopWinOnce(winURL, winWidth, winHeight, winFeatures, winLeft, winTop){
  var d_winLeft = 20  // default, pixels from screen left to window left
  var d_winTop = 20   // default, pixels from screen top to window top
  var popcookies = document.cookie
  if (openPopWinOnce.arguments.length >= 4)  // any additional features? 
    winFeatures = "," + winFeatures
  else 
    winFeatures = "" 
  if (openPopWinOnce.arguments.length == 6)  // location specified
    winFeatures += getLocationOne(winWidth, winHeight, winLeft, winTop)
  else
    winFeatures += getLocationOne(winWidth, winHeight, d_winLeft, d_winTop)
  if (popcookies.indexOf(oneTimeWinName) == -1){ // cookie not found 
    window.open(winURL, oneTimeWinName, "width=" + winWidth 
           + ",height=" + winHeight + winFeatures)
    document.cookie=oneTimeWinName+"=used"
    }
  }
function openPopWinOnceBack(winURL, winWidth, winHeight, winFeatures, winLeft, winTop){
  openPopWinOnce(winURL, winWidth, winHeight, winFeatures, winLeft, winTop)
  self.focus()
  }

function getLocationOne(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
  }