function showPreview(url)
{
    img = document.createElement("img");
    img.src = url;
    img.alt = "";
    img.id = "tempImage"
    tmpImg = document.getElementById("tempImage")
    lb = document.getElementById("lightbox");
    lb.replaceChild(img,tmpImg);
    grey = document.createElement("div");
    grey.id = "greyLayer";
    grey.className = "greyLayer";
    grey.style.height = document.body.clientHeight + "px";
        
    document.body.appendChild(grey);
    lb.style.top = getScrollXY()[1]+getSizeXY()[1]/2-170 + "px";
    lb.style.display = "block";
}

function hidePreview()
{
    document.getElementById("lightbox").style.display = "none";
    document.body.removeChild(document.getElementById("greyLayer"));
}

function getScrollXY() {
  var scrOfX = 0, scrOfY = 0;
  if( typeof( window.pageYOffset ) == 'number' ) {
    //Netscape compliant
    scrOfY = window.pageYOffset;
    scrOfX = window.pageXOffset;
  } else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
    //DOM compliant
    scrOfY = document.body.scrollTop;
    scrOfX = document.body.scrollLeft;
  } else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
    //IE6 standards compliant mode
    scrOfY = document.documentElement.scrollTop;
    scrOfX = document.documentElement.scrollLeft;
  }
  return [ scrOfX, scrOfY ];
}

function getSizeXY() {
  var myWidth = 0, myHeight = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    myWidth = window.innerWidth;
    myHeight = window.innerHeight;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    myWidth = document.documentElement.clientWidth;
    myHeight = document.documentElement.clientHeight;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    myWidth = document.body.clientWidth;
    myHeight = document.body.clientHeight;
  }
  
  return [ myWidth, myHeight ];
}