image gallery next prev (php array in javascript array)

I am trying to create a function with change the picture if I push on the image "prev" oder "next". Actually I have no idea how to realize that, because I get the source of the picture from the database.

$namen = array();
    $mainimg = array();
    $sql1 = mysql_query("SELECT * FROM image WHERE id = ".$id.";");

        echo "<div class='normal'>";

                while($row = mysql_fetch_array($sql1))
    {
        $namen[] = $row['bild']; 
        $mainimg[] = $row['mainimg'];
        $number_array = count($namen);
        ?>
        <script type='text/javascript'>
        <?php
        $php_array = array($row['bild']);
        $js_array = json_encode($php_array);
        echo "var javascript_array = ". $js_array . ";\n";
        ?>
        </script>
        <?php
        if($row['mainimg'] == 1){
            $bild = $row['bild'];
        }

    }


echo "<div class='rahmen'><div class='box'><a href='#' id='opn'><img style='position:absolute;margin:90px 0px 0px 130px;' src='images/lupe.png'>".$path.$bild."\"".$end."</a></div>
<div class='hover1 box1'></div><div onclick='prev()' class='hover2 box2'></div></div>";
echo "<a href='' onclick=\"\"><div id='next'></div></a>";
echo "<a href='' onclick=\"\"><div id='prev'></div></a>";

.rahmen {position:relative;cursor:pointer;}
.box1 { height:64px;width:53px;}
.box2 { height:64px;width:53px;margin-left:347px;}
.hover1 { background:url(images/prev1.png) no-repeat; }
.hover1:hover { background:url(images/prev.png) no-repeat; }
.hover1 { display:none;position:absolute;top:40%;}
div.rahmen:hover .hover1{ display:block;}
.hover2 { background:url(images/next1.png) no-repeat; }
.hover2:hover { background:url(images/next.png) no-repeat;}
.hover2 { display:none;position:absolute;top:40%; }
div.rahmen:hover .hover2{ display:block;}

Now I have the php-array in a javascript array. :-) I have actually two problems: - The click on my image "prev" and "next" doesn't work and I don't know why. Secondly I have no idea how to programm a function which change the image if you push next or prev. Can anybody help me please?

Thanks for your help in advance.

Regards, Yanick