function set_extra_height() {
			document.getElementById('extra').style.height = document.getElementById('text').offsetHeight - 20;;
		}

		function setradio(object) {
			object.checked = true;
		}

		function setcheckbox(object) {
			if (object.checked == false) {
				object.checked = true;
			}
			else {
				object.checked = false;
			}
		}

		function submit_mailinglist() {
			if (document.mailinglist.email.value != "") {
				window.open('http://www.presentationpartner.nl/cgi-bin/newsletter.cgi?email='+document.mailinglist.email.value,'email','toolbar=no,menubar=no,scrollbars=auto,status=no,location=no,directories=no,width=250,height=135,resizable="0",resizable=no');
				document.mailinglist.email.value = "";
			} else {
				document.mailinglist.email.focus();
			}	
			return false;
		}
		
		function popup_video() {
			var w = 320;
			var h = 285;
			LeftPosition = (screen.width) ? (screen.width-w)/2 : 0;
			TopPosition = (screen.height) ? (screen.height-h)/2 : 0;
		
			window.open('http://www.presentationpartner.nl/video/video.html','video','top='+TopPosition+',left='+LeftPosition+',toolbar=no,menubar=no,scrollbars=auto,status=no,location=no,directories=no,width='+w+',height='+h+',resizable="0",resizable=no');
		}

		function popup_pdtv() {
			var w = 800;
			var h = 500;
			LeftPosition = (screen.width) ? (screen.width-w)/2 : 0;
			TopPosition = (screen.height) ? (screen.height-h)/2 : 0;
		
			window.open('http://www.presentationpartner.nl/video/demo_pdtv.html','demo_pdtv','top='+TopPosition+',left='+LeftPosition+',toolbar=no,menubar=no,scrollbars=auto,status=no,location=no,directories=no,width='+w+',height='+h+',resizable="0",resizable=no');
		}