skift månede

Hej
jeg har et lille problem, for jeg ved ikke hvordan jeg får kalender til at skifte mellem månederne.

en der vil hjælpe mig med det?

<font style="font-size: 17pt">Kalender</font><br>
<table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse"  width="100%">
  <tr>
    <td width="128" valign="top">
<?php
include("sql.php");
$query = mysql_query("SELECT * FROM kalender") or die(mysql_error());
$arr = array();
while ($result = mysql_fetch_assoc($query)) {
    $arr[$result['date']] = $result;
}

    $thismonth = ( int ) date( "m" );
    $thisyear = date( "Y" );
 
    $numdaysinmonth = cal_days_in_month( CAL_GREGORIAN, $thismonth, $thisyear );
 
    $jd = cal_to_jd( CAL_GREGORIAN, date( "m" ),date( 1 ), date( "Y" ) );
 
    $startday = jddayofweek( $jd , 0 );
 
    $monthname = jdmonthname( $jd, 1 );
   
    function maandesnavn($monthname)
    {
        if ($monthname == "January")
    {
    echo "Januar";
    }
        elseif ($monthname == "February")
    {
    echo "Februar";
    }
        elseif ($monthname == "March")
    {
    echo "Marts";
    }
        elseif ($monthname == "April")
    {
    echo "April";
    }
        elseif ($monthname == "May")
    {
    echo "Maj";
    }
        elseif ($monthname == "June")
    {
    echo "Juni";
    }
        elseif ($monthname == "July")
    {
    echo "Juli";
    }
        elseif ($monthname == "August")
    {
    echo "August";
    }
        elseif ($monthname == "September")
    {
    echo "September";
    }
        elseif ($monthname == "October")
    {
    echo "Oktober";
    }
        elseif ($monthname == "November")
    {
    echo "November";
    }
        elseif ($monthname == "December")
    {
    echo "December";
    }
    else
    {
        echo "fejl";
    }
    }

?>
<table width="125">
    <tr>
        <td class="kalender" colspan="7"><div align="center"><strong><? maandesnavn($monthname); ?></strong></div></td>
    </tr>
    <tr>
        <td class="kalender"><strong>Søn</strong></td>
        <td class="kalender"><strong>Man</strong></td>
        <td class="kalender"><strong>Tir</strong></td>
        <td class="kalender"><strong>Ons</strong></td>
        <td class="kalender"><strong>Tor</strong></td>
        <td class="kalender"><strong>Fre</strong></td>
        <td class="kalender"><strong>Lør</strong></td>
    </tr>
    <tr>
<?php
    $emptycells = 0;

    for( $counter = 0; $counter <  $startday; $counter ++ ) {
        echo "\t\t<td class=kalender>-</td>\n";
        $emptycells ++;
    }
    $rowcounter = $emptycells;
    $numinrow = 7;
 
    for( $counter = 1; $counter <= $numdaysinmonth; $counter ++ ) {
    $rowcounter ++;
    $dato = sprintf("%04d-%02d-%02d",$thisyear,$thismonth,$counter);
    if(empty($arr[$dato])){
    echo "\t\t<td class=kalender>$counter</td>\n";
    }else{
    $counterdag = $counter;

    //hvis ja, så laver vi link:
    echo "\t\t<td class=kalender><a href=\"?side=kalender&date=$dato&dagen=$counter. ";
    echo maandesnavn($monthname);
    echo " $thisyear\"><b><font color=#000000>$counter</font></b></a></td>\n";
    }
        if( $rowcounter % $numinrow == 0 ) {
            echo "\t</tr>\n";
            if( $counter < $numdaysinmonth ) {
                echo "\t<tr>\n";
            }
            $rowcounter = 0;
        }
    }
    $numcellsleft = $numinrow - $rowcounter;
 
    if( $numcellsleft != $numinrow ) {
 
        for( $counter = 0; $counter < $numcellsleft; $counter ++ ) {
     
            echo "\t\t<td class=kalender>-</td>\n";
            $emptycells ++;
        }
    }

?>
</tr></table>
</td>
  <td width="572" valign="top">
    <table border="0" width="100%">
    <tr>
    <td class="kalenderdag" width="100%"><? $dagen = mysql_real_escape_string($_GET[dagen]); if($_GET[dagen] == ""){echo "..";}else{echo "<b>$dagen</b>";} ?></td>
    </tr>
    <tr>
    <td width="100%">   
    <?
        if($arr[$_GET[date]] == "")
        {
        echo "Der er ikke oprettet nogen event.";
        }
        else
        {
        echo $arr[$_GET[date]][beskrivelse];
        }
    ?>
  </td>
  </tr>
</table>
    </td>
  </tr>
</table>
</body>
</html>