var popupwindow = null;
function initPopup() {
	for(var i = 0; i < document.getElementsByTagName('a').length; i++) {
		var node = document.getElementsByTagName('a')[i];
		if (node.className.match(/^popup(\d+)x(\d+)$/) || node.className.match(/^popup(\d+)x(\d+)\ /)) {

			// change link-behaviour
			node.onclick = function() {
				var reg = /^popup(\d+)x(\d+)$/;
				reg.exec(this.className);
				
				var w = RegExp.$1;
				w = parseInt(w);

				var h = RegExp.$2;
				h = parseInt(h);

				var url=this.getAttribute('href');

				url = url + '?popup=true';

				var padding = 0;

				var screenw = screen.availWidth;
				var screenh = screen.availHeight;
				var winw = (w + padding);
				var winh = (h + padding);
				var posx = (screenw / 2) - (winw / 2);
				var posy = (screenh / 2) - (winh / 2);
				
				if (popupwindow) {
					popupwindow.close();
				}
				
				popupwindow = window.open(url,"popupwindow","top="+posy+",left="+posx+",width="+winw+",height="+winh+",menubar=no,locationbar=no,statusbar=no,resizable=no,toolbar=no,dependent=no,scrollbars=yes,X=0,Y=0");
				popupwindow.focus(); 
				return !popupwindow;

			}	
		}
	}
}

addInitFunction(initPopup);