var posX = 0; 
var posY = 0; 
var lastImageSrc = "";

/* INITIALISIEREN */
if(document.all) { 
  document.onmousemove = mouseMove_event; 
}
else {
  document.onmousemove = mouseMove_normal;
}

/* Mausposition finden für Browser mit Event-Objekt */
function mouseMove_event(e){
  posX = event.clientX; 
  posY = event.clientY;
}

/* Mausposition finden für Browser ohne Event-Objekt */
function mouseMove_normal(e){
  posX = e.pageX; 
  posY = e.pageY;
}

/* Div verschieben */
function moveDiv(viewerObject,imageWidth,imageHeight) {
  if(document.all) {
    if(self.pageYOffset) {
      posX += self.pageXOffset;
      posY += self.pageYOffset;
    }
    else if(document.documentElement && document.documentElement.scrollTop) {
      posX += document.documentElement.scrollLeft;
	    posY +=document.documentElement.scrollTop;
    }
    else if(document.body) {
      posX += document.body.scrollLeft;
      posY += document.body.scrollTop;
    }
  }
  viewerObject.style.left = (posX-imageWidth-30) + "px";
  viewerObject.style.top = (posY-imageHeight/2) + "px";
}

/* Div verstecken */
function hideImage() {
  document.getElementById("imageViewer").style.display = "none";
  document.getElementById("imageViewerImg").src = "img/blank.gif";
  lastImageSrc = "";
}

/* Div anzeigen */
function showImage(imageSrc,imageComment,imageWidth,imageHeight) {
  var viewerObject = document.getElementById("imageViewer");
  document.getElementById("imageViewerImg").src = "img/blank.gif";
  document.getElementById("imageViewerText").innerHTML = imageComment;
  
  if( lastImageSrc != imageSrc ){
    document.getElementById("imageViewerImg").src = imageSrc;
    if(imageWidth > 0 && imageHeight > 0){
    document.getElementById("imageViewerImg").width= imageWidth;
    document.getElementById("imageViewerImg").height= imageHeight;
    }
    lastImageSrc = imageSrc;
  }

  moveDiv(viewerObject,imageWidth,imageHeight);
  viewerObject.style.display = "block";
}