function displayCardField( nPage )
{

    var nCount = 0;

    while ( $( 'cardfield_' + nCount ) )
	{
		$( 'cardfield_' + nCount ).style.display = 'none';
		$( 'url_' + nCount ).className = 'navigators';
		nCount = nCount + 1;
	}

	$( 'cardfield_' + nPage ).style.display = 'block';
	$( 'url_' + nPage ).className = 'navigators navigatoractive';


}

function addAddress( sEmail, sName )
{

	var i;

	//add new element (option)
	var elOptNew = document.createElement('option');
	
	if ( sName )
	{
    	elOptNew.text  = sName + ' <' + sEmail + '>';
    	elOptNew.value = sName + ' <' + sEmail + '>';
	}
	else
	{
	    elOptNew.text  = sEmail;
    	elOptNew.value = sEmail;
	}

	try {
	    $( 'to' ).options.add(elOptNew, null); // standards compliant; doesn't work in IE
	}
	catch(ex) {
		$( 'to' ).options.add(elOptNew); // IE only
	}

}

function removeAddresses( sElement )
{

    var i;

    //remove elements
	for (i = $( sElement ).length - 1; i >= 0; i--)
		if ( $( sElement ).options[ i ].selected )
			$( sElement ).remove( i );

}

function addAddresses()
{

    var aSelectedValue = new Array();
	var aSelectedText  = new Array();
	var i;

	for ( i = 0; i < $( 'addresses' ).options.length; i++ )
	{
		if ( $( 'addresses' ).options[ i ].selected )
			aSelectedText.push( $( 'addresses' ).options[ i ].text );
	}

	//add elements
	for ( i = 0; i < aSelectedText.length; i++ )		
		addAddress( aSelectedText[ i ], '' );

    removeAddresses( 'addresses' );
}

function addButton( sText, sMail )
{

var i;

	//add new element (option)
	var elOptNew = document.createElement('option');
	
    elOptNew.text  = sText;
    elOptNew.value = sText + '||' + sMail;

	try {
	    $( 'buttons' ).options.add(elOptNew, null); // standards compliant; doesn't work in IE
	}
	catch(ex) {
		$( 'buttons' ).options.add(elOptNew); // IE only
	}

}

function displayInfo( nId )
{

    var nWidth  = 500;
    var nHeight = 500;

    window.open( '/info.php?id=' + nId, 'info', 'width=' + nWidth + ', height=' + nHeight + ', left=' + (screen.availWidth - nWidth) / 2 + ', top=' + (screen.availHeight - nHeight) / 2 + ', resizable, scrollbars' );
}

function validateInformation()
{

    var sErrors = '';

    if ( !$( 'from_email' ).value )
        sErrors = sErrors + "\n- Afzender e-mailadres is leeg.";
    if ( !$( 'from_name' ).value )
        sErrors = sErrors + "\n- Afzender naam is leeg.";
    if ( $( 'to' ).length <= 0 )
        sErrors = sErrors + "\n- Lijst met ontvangers is leeg.";
    if ( !$( 'message' ).value )
        sErrors = sErrors + "\n- Persoonlijke boodschap is leeg.";

    if ( sErrors )
    {
        alert( "Kaart kan niet verstuurd worden omdat de volgende gegevens missen:\n" + sErrors );
        return false;
    }

    for ( i = 0; i < $( 'to' ).options.length; i++ )
        $( 'to' ).options[ i ].selected = true;
    for ( i = 0; i < $( 'buttons' ).options.length; i++ )
        $( 'buttons' ).options[ i ].selected = true;

    return true;
}

function selectAddresses()
{

    for ( i = 0; i < $( 'to' ).options.length; i++ )
        $( 'to' ).options[ i ].selected = true;
}