function LayerLibShowPopup(purl, pwidth, pheight, ppad)
{
	// defaults
	if ( !isFinite(pwidth) )  { pwidth = 640; }
	if ( !isFinite(pheight) ) { pheight = 500; }
	if ( !isFinite(ppad) )    { ppad = 10; }

	var scroll = self.pageYOffset||document.body.scrollTop||document.documentElement.scrollTop;
	var top = scroll + 150;

	// shadow effect
	var objOverlay = document.getElementById('layerlib_overlay');
	var yScroll;
	if (window.innerHeight && window.scrollMaxY) {
		yScroll = window.innerHeight + window.scrollMaxY;
	} else {
		yScroll = document.body.scrollHeight||document.body.offsetHeight;
	}
	var winHeight = self.innerHeight||document.body.clientHeight||document.documentElement.clientHeight;
	var pageHeight = (yScroll < winHeight) ? winHeight : yScroll;
	objOverlay.style.height = pageHeight + 'px';
	objOverlay.style.display = 'block';

	var objIFrame = document.getElementById('layerlib_iframe');
	objIFrame.style.width = pwidth + 'px';
	objIFrame.style.height = pheight + 'px';
	objIFrame.src = purl;

	var objPopup = document.getElementById('layerlib_popup');
	objPopup.style.width = pwidth + 'px';
	objPopup.style.position = 'absolute';
	objPopup.style.left = (document.documentElement.offsetWidth/2 - pwidth/2) + 'px';
	objPopup.style.top = top + 'px';
	objPopup.style.padding = ppad + 'px';
	objPopup.style.display = 'block';
}

function LayerLibClosePopup()
{
	document.getElementById('layerlib_popup').style.display = 'none';
	document.getElementById('layerlib_overlay').style.display = 'none';
}