var popUpWindow;
var imageTitle;
var imageURL;

function writeStyleSheetLinks()
{
  if (navigator.appName == "Microsoft Internet Explorer") {
    document.write('<link rel="stylesheet" type="text/css" href="../css/globalIE.css" />');
  } else {
    document.write('<link rel="stylesheet" type="text/css" href="../css/globalW3C.css" />');
  }

  document.write('<link rel="stylesheet" type="text/css" href="../css/observatory.css" />');
}

function handleMouseOverOfTableCellWithOverlay(cell, overlay)
{
  if (overlay > 0) {
    setDisplayAttributeOfOverlayWithNumber("block", overlay);
  }
  
  cell.style.backgroundImage = "url(../images/reflection_2.png)";
}

function handleMouseOutOfTableCellWithOverlay(cell, overlay)
{
  if (overlay > 0) {
    setDisplayAttributeOfOverlayWithNumber("none", overlay);
  }

  cell.style.backgroundImage = "url(../images/reflection_1.png)";
}

function setDisplayAttributeOfOverlayWithNumber(attribute, number)
{ 
  var string = 'overlay_' + number;
  var overlay = document.getElementById(string);
    
  overlay.style.display = attribute;
}

function showImageWithTitleURL(title, url)
{
  if (!popUpWindow) {
    popUpWindow = window.open('../popup.html', 'popUp', 'width=420, height=420, status=no, scrollbars=no');
  }
  
  imageTitle = title;
  imageURL = url;
  
  changeImage();
}

function changeImage()
{
  var newImage = new Image();
  var oldImage;
  
  newImage.onload = function() {
    var width = newImage.width + 20;
    var height = newImage.height + 40;
    
    oldImage.style.display = 'none';
    popUpWindow.resizeTo(width, height);

    oldImage.src = 'observatory/' + imageURL;
    oldImage.style.display = 'block';
  }

  oldImage = popUpWindow.document.getElementById('magnification');

  if (oldImage == null) {    
    setTimeout('changeImage()', 50);
  } else {
    popUpWindow.document.title = imageTitle;
    newImage.src = imageURL;
  }
}

function hideImage()
{
  if (popUpWindow) {
    popUpWindow.close();
  }
}