var popupImage = new Image();
var imageWidth, imageHeight;
function showPic (whichpic) {
if (document.getElementById) {
  document.getElementById('placeholder').src = whichpic.href;
  popupImage.src = document.getElementById('placeholder').src.replace(/L/, "XL");
  document.getElementById('desc').innerHTML = document.getElementById('com' + whichpic.id).innerHTML;
  	}
imageWidth = popupImage.width;
imageHeight = popupImage.height;
return false;
}


function showLarge() {
popupImage.src = document.getElementById('placeholder').src.replace(/L/, "XL");
imageWidth = popupImage.width;
imageHeight = popupImage.height;
var scrollX, scrollY, centerX, centerY, leftOffset, topOffset;

if( self.pageYOffset ) {
  scrollX = self.pageXOffset;
  scrollY = self.pageYOffset;
} else if( document.documentElement && document.documentElement.scrollTop ) {
  scrollX = document.documentElement.scrollLeft;
  scrollY = document.documentElement.scrollTop;
} else if( document.body ) {
  scrollX = document.body.scrollLeft;
  scrollY = document.body.scrollTop;
}
if( self.innerHeight ) {
  centerX = self.innerWidth;
  centerY = self.innerHeight;
} else if( document.documentElement && document.documentElement.clientHeight ) {
  centerX = document.documentElement.clientWidth;
  centerY = document.documentElement.clientHeight;
} else if( document.body ) {
  centerX = document.body.clientWidth;
  centerY = document.body.clientHeight;
}

/*alert('width:' + imageWidth + ', height:' + imageHeight);*/
bigImage = document.getElementById("popup");
leftOffset = scrollX + (centerX - imageWidth) / 2;
topOffset = scrollY + (centerY - imageHeight) / 2;
bigImage.innerHTML = '<img id="popupImage" src="' + popupImage.src + '" style="position:absolute; top: ' + topOffset + 'px; left: ' + leftOffset + 'px;">';
bigImage.style.visibility = "visible";
/*alert('width:' + imageWidth + ', height:' + imageHeight + ', scroll x/y:' + scrollX + '/' + scrollY + 'left/top' + leftOffset + '/' + topOffset);*/

}

function hideImage() {
document.getElementById("popup").style.visibility = "hidden";
}