var popWin = null 
var winCount = 0
var winName = "popWin"
function newPopUp(winURL, winTitle, winWidth, winHeight, winFeatures, winLeft, winTop){
  //winHeight = screen.height;
 // winWidth = screen.width;
  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
  winName = winTitle;
	closePopWin()           // close any previously opened pop-up window
  if (newPopUp.arguments.length >= 5)  // any additional features? 
    winFeatures = "," + winFeatures;
  else 
    winFeatures = "" ;
  if (newPopUp.arguments.length == 7)  // 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){
  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;
  }