// Funktion Bilderwechsel
function wechsel(Obj,bild){
	Obj.src=bild;
}

function printPage() {
var da = (document.all) ? 1 : 0;
var pr = (window.print) ? 1 : 0;
var mac = (navigator.userAgent.indexOf("Mac") != -1); 
if (pr) // NS4, IE5
    window.print()
  else if (da && !mac) // IE4 (Windows)
    vbPrintPage()
  else  // other browsers
  {
   alert("Sorry, your browser doesn't support this feature.");
   return false;
  }

	if (da && !pr && !mac) with (document) {
	  writeln('<OBJECT ID="WB" WIDTH="0" HEIGHT="0" CLASSID="clsid:8856F961-340A-11D0-A96B-00C04FD705A2"></OBJECT>');
	  writeln('<' + 'SCRIPT LANGUAGE="VBScript">');
	  writeln('Sub window_onunload');
	  writeln('  On Error Resume Next');
	  writeln('  Set WB = nothing');
	  writeln('End Sub');
	  writeln('Sub vbPrintPage');
	  writeln('  OLECMDID_PRINT = 6');
	  writeln('  OLECMDEXECOPT_DONTPROMPTUSER = 2');
	  writeln('  OLECMDEXECOPT_PROMPTUSER = 1');
	  writeln('  On Error Resume Next');
	  writeln('  WB.ExecWB OLECMDID_PRINT, OLECMDEXECOPT_DONTPROMPTUSER');
	  writeln('End Sub');
	  writeln('<' + '/SCRIPT>');
	}
}

/*
 Section: email validation
*/

	function email_validate(str){
		/*
			requires: String(email address)
			returns: Boolean(true | false);

			this validator checks email addresses for the following criteria:
			
			- NO existence of DOUBLE PERIODS in a row
			- does NOT BEGIN or END with periods
			- does NOT BEGIN or END with the 'at' symbol
			- contains NO WHITESPACE as defined by regular expressions
			- contains only ONE instance of the 'at' (@) symbol
			- the DOMAIN address contains at least ONE period
			
			if inconsistencies are found, they are reported to the user so that
			changes can be made
		*/
	
		// regular expression configuration	
		var dots_double = new RegExp("\\.\\.");
		var dots_begin = new RegExp("^\\.");
		var dots_end = new RegExp("\\.$");
		var ats_begin = new RegExp("^@");
		var ats_end = new RegExp("@$");
		var white_space = new RegExp("\\s");
		
		// boolean evaluations
		var at_exists = (str.search(/\@/) != -1);
		var at_only_one = false;
		var dot_one_after_at = false;
		
		if(at_exists){	// if no 'at' symbol exists, the following are obsolete
			var at_only_one = (Number((str.split("@").length)-1) == 1);
			var dot_one_after_at = (Number(str.split("@")[1].search(/\./)) != -1);
		}
		
		// regular expression evaluations
		var e_dots_double = dots_double.test(str);
		var e_dots_begin_end = (dots_begin.test(str) || dots_end.test(str));
		var e_ats_begin_end = (ats_begin.test(str) || ats_end.test(str));
		var e_at_only_one = at_only_one;
		var e_white_space = white_space.test(str);
		var e_dot_one_after_at = dot_one_after_at;

		// final evaluation
		var valid_email = Boolean((!e_dots_double) && (!e_dots_begin_end) && (!e_ats_begin_end)
			&& (e_at_only_one) && (!e_white_space) && (e_dot_one_after_at));
		
		
		if(valid_email){
			return true;	// email successfully validated
		}
		else{
			// capture and handle errors in the provided email structure
			var error_msg = "";
			if(e_dots_double){
				error_msg = "punten (.) moeten gescheiden worden door leestekens";
			}
			else if(e_dots_begin_end){
				error_msg = "een geldig e-mailadres kan niet beginnen of eindigen met een punt (.)";
			}
			else if(e_ats_begin_end){
				error_msg = "een geldig e-mailadres kan niet beginnen of eindigen met een apestaartje (@)";
			}
			else if(!at_exists){
				error_msg = "een apestaartje (@) is verplicht in een geldig e-mailadres";
			}
			else if(!e_at_only_one){
				error_msg = "er is maar één apestaartje (@) toegestaan in een geldig e-mailadres";
			}
			else if(e_white_space){
				error_msg = "er is geen lege ruimte (spatie, tab, nieuwe regel, enter, etc) " + 
					"toegestaan in een e-mailadres";
			}
			else if(!e_dot_one_after_at){
				error_msg = "een geldig e-mailadres domein bevat minstens één punt (.)";
			}

			var email_example = "voornaam.achternaam@domein.nl";
			var email_explain = "een geldig e-mailadres bestaat uit een gebruikersnaam, en een apestaartje (@), " +
				"en een domein adres.  Bijvoorbeeld...\n -  " + email_example;
				
			alert(error_msg + "\n -  " + str + "\n\n" + email_explain);
			
			return false;
		}
	}
// end section

/*
 Section: compatibility functions for Netscape and IE
*/
	function isDefined(variable){
		if(navigator.appName == "Netscape"){
			return (!(variable == undefined));
		}
		else{ // (navigator.appName == "Microsoft Internet Explorer"){
			return (!(variable == null));
		}
	}

	function isEmpty(variable){
		if(	(!isDefined(variable)) ||
			(variable == "") ||
			(variable == null) )
		{	
			return true;
		}

		return false;
	}
// end section


/*
 Section: highlight the field needing corrections
*/
	function highlight(txt, mark){
		// Boolean: mark (mark the form object)
		// [Form Object].[text]: txt
		if(!mark){
			txt.focus();
		}
	}
// end section


function zekerweten() {
  return confirm("Weet u zeker dat u de Conrad nieuwsbrief niet meer wilt ontvangen?");

}