// create a pop-up window
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 = 20 // default, pixels from screen left to window left
 var d_winTop = 20  // 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 Microshit 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
 }