function popupWindow (url, windowName, width, height) {
var siteWindow = null
	if (!siteWindow || siteWindow.closed) {
		siteWindow = window.open(url,windowName,'toolbar=no,width='+width+',height='+height+',status=no,scrollbars=1,resize=yes,menubar=no,left=20,top=20')
	}
	siteWindow.focus();
}