function openPage(url,w,h) {
	l=screen.width/2-w/2;
	t=screen.height/2-h/2;
	if (typeof myWindow == "object") {
	    myWindow.close();	
	}
	myWindow = window.open(url,'ProgrammeNotes','top='+t+',left='+l+',height='+h+',width='+w+',noresize,scrollbars=yes,status=no');
}