function launchwin (url, w, h, name) {
	screenw = screen.availWidth;
   	screenh = screen.availHeight;

   var leftPos = (screenw-w)/2, topPos = (screenh-h)/2;
   var params = "toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=true,resizable=true,width=" + w + ",height=" + h + ",top=" + topPos + ",left=" + leftPos;
   newWindow=window.open(url,name, params);
   if (newWindow.opener == null) newWindow.opener = self;
   newWindow.focus();  
}