Thank you for your help,
This is the code. Nothing is missing, now
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"[url="http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"]http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd[/url]">
<html xmlns="[url="http://www.w3.org/1999/xhtml"]http://www.w3.org/1999/xhtml[/url]" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf8_unicode_ci" />
<title></title>
<link rel= "stylesheet" href="menu_style.css" type="text/css" />
<link href="opmaak.css" rel="stylesheet" type="text/css"/>
</head>
<?php
include 'navigatie/nav6.inc';
?>
<div id="container">
<div id="header3">
<html>
<head>
<?
include ("db_connect.inc.php");
$query = "SELECT * FROM rooster
";; // de SQL-query die wordt uitgevoerd
$resultaat = ""; // hierin wordt het resultaat van de query opgeslagen
$resultaat = mysql_query($query, $db);
mysql_close($db);
?>
<h2>Rooster</h2>
<hr>
<?php
while(list($roosterid, $ma, $kls,$ge,$f101,$extra, $urid, $urma, $urclass, $urge, $urf101) = mysql_fetch_row($resultaat)){
echo "<P>$kls";
echo "<BR><a href=\"make.php?id=$roosterid\"></a><br>Fill in";
}
?>
</body>
</html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"[url="http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"]http://www.w3.org/TR...tml1-strict.dtd[/url]">
<html xmlns="[url="http://www.w3.org/1999/xhtml"]http://www.w3.org/1999/xhtml[/url]" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf8_unicode_ci" />
<title></title>
<link rel= "stylesheet" href="menu_style.css" type="text/css" />
<link href="opmaak.css" rel="stylesheet" type="text/css"/>
</head>
</head>
<?php
include 'navigatie/nav6.inc';
?>
<div id="container">
<div id="header3">
<html>
<head>
</head>
<body>
<?php
include ("db_connect.inc.php");
// controleren of pagina zichzelf heeft aangeroepen
// via hidden field " bevestiging" van formulier
if (isset($_POST["bevestiging"])){
// query samenstellen
// LET OP: in werkelijkheid nog validatie uitvoeren van de gegevens in $_POST
$query = "UPDATE rooster SET
ma = '". $_POST["ma"] ."',
kls = '". $_POST["kls"] ."',
goe = '". $_POST["ge"] ."',
f101 = '". $_POST["f101"] ."'
WHERE roosterid='" .$_POST["id"] ."'";
mysql_query($query);
$query = "UPDATE tw SET
urma = '". $_POST["urma"] ."',
urclass = '". $_POST["urclass"] ."',
urge = '". $_POST["urge"] ."',
urf101 = '". $_POST["urf101"] ."'
WHERE urid='" .$_POST["id"] ."'";
mysql_query($query);
echo "<h2>Rooster</h2>De volgende opdracht is uitgevoerd: <b>$query</b><br><hr>\n";
echo "Record nummer " .$_POST["id"] . " is bijgewerkt<br>\n";
echo "<a href=\"wijzigen.php\">Terug naar wijzigen.</a>";
}
else{
// pagina heeft zichzelf nog niet aangeroepen, gegevens inlezen
$query="SELECT * FROM rooster INNER JOIN tw ON roosterid=urid WHERE roosterid='". $_GET["id"] ."'";
$resultaat = mysql_query($query);
while (list($roosterid, $ma, $kls,$ge,$f101,$extra, $urid, $urma, $urclass, $urge, $urf101 ) = mysql_fetch_row($resultaat)){
$vn=$ma;
$vm=$kls;
$aa=$ge;
$ab=$f101;
$ac=$urge;
$ad=$urf101;
}
?>
<form action="<?php echo($_SERVER["PHP_SELF"]);?>" method="post">
<input type="hidden" name="bevestiging" value="1">
<input type="hidden" name="id" value="<?php echo $_GET["id"];?>">
<h2>wijzigen</h2>
Kls:<input type="text" name="kls"
value="<?php echo$vm;?>" size="50""><br>
Dag
<input type="checkbox" name="ma" <?php if (!empty($vn)) {echo 'checked="checked"';} ?> value="ma""/>ma
<br>Eerste
<input type="checkbox" name="ge" <?php if (!empty($aa)) {echo 'checked="checked"';} ?> value="ge""/>ge
<input type="checkbox" name="f101" <?php if (!empty($ab)) {echo 'checked="checked"';} ?> value="f101""/>101
<br>Tweede
<input type="checkbox" name="urge" <?php if (!empty($ac)) {echo 'checked="checked"';} ?> value="ge""/>ge
<input type="checkbox" name="urf101" <?php if (!empty($ad)) {echo 'checked="checked"';} ?> value="utf101""/>101
<hr>
<input type="Submit" value="Registreer de gegevens.">
</form>
<?php
}// else-blok afsluiten
?>
</body>
</html>
</div>