function popup(popup_content, popup_overlay_id, popup_window_id)
{
	// define default values if applicable
	if (!xDef(popup_overlay_id)) { popup_overlay_id = 'popup_overlay'; }
	if (!xDef(popup_window_id)) { popup_window_id = 'popup_window'; }

	popup_overlay_div = xGetElementById(popup_overlay_id);
	popup_window_div = xGetElementById(popup_window_id);

	if (xDef(popup_content)) // show popup
	{
		xLeft(popup_overlay_id, xScrollLeft());
		xTop(popup_overlay_id, xScrollTop());
		xWidth(popup_overlay_id, xClientWidth());
		xHeight(popup_overlay_id, xClientHeight());
		xDisplay(popup_overlay_id, 'block');
		
		xInnerHtml(popup_window_id, '<div class="popupClose" onclick="popup()">x</div>' + popup_content);
		xDisplay(popup_window_id, 'block');
		if (xDef(popup_content_width)) { xWidth(popup_window_id, popup_content_width); }
		if (xDef(popup_content_height)) { xHeight(popup_window_id, popup_content_height); }
		xLeft(popup_window_id, xScrollLeft() + (xClientWidth() - xWidth(popup_window_id)) / 2);
		xTop(popup_window_id, xScrollTop() + (xClientHeight() - xHeight(popup_window_id)) / 2);
		
		popup_overlay_div.onclick = popup_event;
	}

	else // clear popup
	{
		xDisplay(popup_overlay_id, 'none');
		xDisplay(popup_window_id, 'none');
		xInnerHtml(popup_window_id, '');

		popup_overlay_div.onclick = null;
	}
}

function popup_event(e)
{
	if (!e) e = window.event;
	popup(); // clear popup
	return true;
}

function popup_init()
{
	window.onscroll = popup_event;
	window.onresize = popup_event;
}

/* Portion of az_popup.js compiled from X 4.0 with XC 0.28b. Distributed under GNU LGPL. For copyrights, license, documentation and more visit Cross-Browser.com */
var xOp7Up,xOp6Dn,xIE4Up,xIE4,xIE5,xNN4,xUA=navigator.userAgent.toLowerCase();if(window.opera){var i=xUA.indexOf('opera');if(i!=-1){var v=parseInt(xUA.charAt(i+6));xOp7Up=v>=7;xOp6Dn=v<7;}}else if(navigator.vendor!='KDE' && document.all && xUA.indexOf('msie')!=-1){xIE4Up=parseFloat(navigator.appVersion)>=4;xIE4=xUA.indexOf('msie 4')!=-1;xIE5=xUA.indexOf('msie 5')!=-1;}else if(document.layers){xNN4=true;}xMac=xUA.indexOf('mac')!=-1;function xClientHeight(){var h=0;if(xOp6Dn) h=window.innerHeight;else if(document.compatMode == 'CSS1Compat' && !window.opera && document.documentElement && document.documentElement.clientHeight)h=document.documentElement.clientHeight;else if(document.body && document.body.clientHeight)h=document.body.clientHeight;else if(xDef(window.innerWidth,window.innerHeight,document.width)) {h=window.innerHeight;if(document.width>window.innerWidth) h-=16;}return h;}function xClientWidth(){var w=0;if(xOp6Dn) w=window.innerWidth;else if(document.compatMode == 'CSS1Compat' && !window.opera && document.documentElement && document.documentElement.clientWidth)w=document.documentElement.clientWidth;else if(document.body && document.body.clientWidth)w=document.body.clientWidth;else if(xDef(window.innerWidth,window.innerHeight,document.height)) {w=window.innerWidth;if(document.height>window.innerHeight) w-=16;}return w;}function xDef(){for(var i=0; i<arguments.length; ++i){if(typeof(arguments[i])=='undefined') return false;}return true;}function xDisplay(e,s){if(!(e=xGetElementById(e))) return null;if(e.style && xDef(e.style.display)) {if (xStr(s)) e.style.display = s;return e.style.display;}return null;}function xGetComputedStyle(oEle, sProp, bInt){var s, p = 'undefined';var dv = document.defaultView;if(dv && dv.getComputedStyle){s = dv.getComputedStyle(oEle,'');if (s) p = s.getPropertyValue(sProp);}else if(oEle.currentStyle) {var a = sProp.split('-');sProp = a[0];for (var i=1; i<a.length; ++i) {c = a[i].charAt(0);sProp += a[i].replace(c, c.toUpperCase());}   p = oEle.currentStyle[sProp];}else return null;return bInt ? (parseInt(p) || 0) : p;}function xGetElementById(e){if(typeof(e)!='string') return e;if(document.getElementById) e=document.getElementById(e);else if(document.all) e=document.all[e];else e=null;return e;}function xHeight(e,h){if(!(e=xGetElementById(e))) return 0;if (xNum(h)) {if (h<0) h = 0;else h=Math.round(h);}else h=-1;var css=xDef(e.style);if (e == document || e.tagName.toLowerCase() == 'html' || e.tagName.toLowerCase() == 'body') {h = xClientHeight();}else if(css && xDef(e.offsetHeight) && xStr(e.style.height)) {if(h>=0) {var pt=0,pb=0,bt=0,bb=0;if (document.compatMode=='CSS1Compat') {var gcs = xGetComputedStyle;pt=gcs(e,'padding-top',1);if (pt !== null) {pb=gcs(e,'padding-bottom',1);bt=gcs(e,'border-top-width',1);bb=gcs(e,'border-bottom-width',1);}else if(xDef(e.offsetHeight,e.style.height)){e.style.height=h+'px';pt=e.offsetHeight-h;}}h-=(pt+pb+bt+bb);if(isNaN(h)||h<0) return;else e.style.height=h+'px';}h=e.offsetHeight;}else if(css && xDef(e.style.pixelHeight)) {if(h>=0) e.style.pixelHeight=h;h=e.style.pixelHeight;}return h;}function xInnerHtml(e,h){if(!(e=xGetElementById(e)) || !xStr(e.innerHTML)) return null;var s = e.innerHTML;if (xStr(h)) {e.innerHTML = h;}return s;}function xLeft(e, iX){if(!(e=xGetElementById(e))) return 0;var css=xDef(e.style);if (css && xStr(e.style.left)) {if(xNum(iX)) e.style.left=iX+'px';else {iX=parseInt(e.style.left);if(isNaN(iX)) iX=0;}}else if(css && xDef(e.style.pixelLeft)) {if(xNum(iX)) e.style.pixelLeft=iX;else iX=e.style.pixelLeft;}return iX;}function xNum(){for(var i=0; i<arguments.length; ++i){if(isNaN(arguments[i]) || typeof(arguments[i])!='number') return false;}return true;}function xScrollLeft(e, bWin){var offset=0;if (!xDef(e) || bWin || e == document || e.tagName.toLowerCase() == 'html' || e.tagName.toLowerCase() == 'body') {var w = window;if (bWin && e) w = e;if(w.document.documentElement && w.document.documentElement.scrollLeft) offset=w.document.documentElement.scrollLeft;else if(w.document.body && xDef(w.document.body.scrollLeft)) offset=w.document.body.scrollLeft;}else {e = xGetElementById(e);if (e && xNum(e.scrollLeft)) offset = e.scrollLeft;}return offset;}function xScrollTop(e, bWin){var offset=0;if (!xDef(e) || bWin || e == document || e.tagName.toLowerCase() == 'html' || e.tagName.toLowerCase() == 'body') {var w = window;if (bWin && e) w = e;if(w.document.documentElement && w.document.documentElement.scrollTop) offset=w.document.documentElement.scrollTop;else if(w.document.body && xDef(w.document.body.scrollTop)) offset=w.document.body.scrollTop;}else {e = xGetElementById(e);if (e && xNum(e.scrollTop)) offset = e.scrollTop;}return offset;}function xStr(s){for(var i=0; i<arguments.length; ++i){if(typeof(arguments[i])!='string') return false;}return true;}function xTop(e, iY){if(!(e=xGetElementById(e))) return 0;var css=xDef(e.style);if(css && xStr(e.style.top)) {if(xNum(iY)) e.style.top=iY+'px';else {iY=parseInt(e.style.top);if(isNaN(iY)) iY=0;}}else if(css && xDef(e.style.pixelTop)) {if(xNum(iY)) e.style.pixelTop=iY;else iY=e.style.pixelTop;}return iY;}function xWidth(e,w){if(!(e=xGetElementById(e))) return 0;if (xNum(w)) {if (w<0) w = 0;else w=Math.round(w);}else w=-1;var css=xDef(e.style);if (e == document || e.tagName.toLowerCase() == 'html' || e.tagName.toLowerCase() == 'body') {w = xClientWidth();}else if(css && xDef(e.offsetWidth) && xStr(e.style.width)) {if(w>=0) {var pl=0,pr=0,bl=0,br=0;if (document.compatMode=='CSS1Compat') {var gcs = xGetComputedStyle;pl=gcs(e,'padding-left',1);if (pl !== null) {pr=gcs(e,'padding-right',1);bl=gcs(e,'border-left-width',1);br=gcs(e,'border-right-width',1);}else if(xDef(e.offsetWidth,e.style.width)){e.style.width=w+'px';pl=e.offsetWidth-w;}}w-=(pl+pr+bl+br);if(isNaN(w)||w<0) return;else e.style.width=w+'px';}w=e.offsetWidth;}else if(css && xDef(e.style.pixelWidth)) {if(w>=0) e.style.pixelWidth=w;w=e.style.pixelWidth;}return w;}