function openWBT() {
				var wbtPath = "http://hea.learning-suite.de/Basiswissen_Stromanwendung_CL/";
				var username = "hea";
				var password = "hea";
				var anonymous = "true";
				var wbtUnique = "BasiswissenStromanwendungBDEW";
				var wbtWindow = window.open( wbtPath + "main.cfm?usn=" + username + "&pwd=" + password + "&anonymousLogin=" + anonymous, wbtUnique, 'toolbar=no,statusbar=no,location=no,scrollbars=no,menubar=no,top=' + ( Math.max( 0, parseInt( ( screen.availHeight - 653 ) / 2 ) ) ) + ',left=' + ( Math.max( 0, parseInt( ( screen.availWidth - 991 ) / 2 ) ) ) + ',height=653,width=991' );
				wbtWindow.focus();
			};