Combo box does not change result

[artfuldodger]

I have this code below that creates a combo dropdown list that the user can use to select how many images ($MAXEMLEMENTSPERPAGE)I have set caption to be 1 the problem is I can't figure out how to get the combo box change the value of the user selected to loadthat page and shows the number of images the user wants I am using $xml = simplexml_load_file("xml/images.xml"); to load the image elements and then $maxpage to paginate the images if I change $cation to 5 then it displays 5 images per page the problem I have is at the moment I haven't found a way of passing the selected value to $caption to refresh the
page with its new value

select name="mydropdownlist">
    <?php
    $caption = 1;                      
 
    $options = array('2' => '2',
                     '3' => '3',
                     '4' => '4');
 
            foreach($options as $value => $caption)
       { 
                if(isset($_GET['caption']))
        {
            $caption = $_GET['caption'];   //if page is specif
        }
                    echo "<option value=\"$value\" selected=\"$value\">$caption</option>";
 
       }
    ?>
 </select>
<?php
    $page = 0;
    $MAXELEMENTSPERPAGE = $caption; //change this value to display how many elements per page you wish people to see
    $maxPage = count($xml)/$MAXELEMENTSPERPAGE;
 
    if(isset($_GET['page']))
    {
        $page = $_GET['page'];   //if page is specif
    }
 
    ?> <?php
    for($i =$page * $MAXELEMENTSPERPAGE ; $i< ($page * $MAXELEMENTSPERPAGE ) +$MAXELEMENTSPERPAGE ; $i++)
                    {
                        //start the foreach loop
                        $imageProp = $i;
 
                        if($i >= count($xml))
                        {
                            break;
                        }
 ?>
 Page:
<?php
if($page > 0){
    ?>
    <a href=<?php echo $_SERVER["PHP_SELF"]."?page=".($page-1); ?>>Previous </a>
    <?php
}
 
for($i = 0; $i< $maxPage; $i++ ){
    //here we are making a loop for how many pages we have
    //we then spawn a hyperlink for each page
    //$Server["php_self"]  returns the current page url
    //then we append the page number to it
 
    ?>
 
    <a href=<?php echo $_SERVER["PHP_SELF"]."?page=".$i; ?>><?php echo $i;?></a>
    <?php
}
?>
<?php
if($page < floor($maxPage)){
    ?>
 
    <a href=<?php echo $_SERVER["PHP_SELF"]."?page=".($page+1); ?>> Next </a>
    <?php
}
?>

I am a newbie to php any help would be appreciated