// Use this function to control placement of pop-up window
  // in Netscape 4+ and Internet Explorer 4+
  function openPopImgWin(imgWinName, windowWidth, windowHeight){
    var leftX = 20  // distance of window's left side from left of screen
    var topY = 20   // distance of window's top side from top of screen
    var winFeatures = "toolbar=no,scrollbars=no,resizable=no,width=" 
      + windowWidth + ",height=" + windowHeight
    if (leftX>0){
      winFeatures += ",screenX=" + leftX + ",left=" + leftX	
                  + ",screenY=" + topY + ",top=" + topY
      }
    return window.open("pimg.html", imgWinName, winFeatures)
    }