Refinement bar with multiple options submitted - php

Question

I am trying to create a refinement bar with multiple filter options submitted in the form. Currently I have the form just submitting one option, can someone please tell me what I am missing in my code?
<form action="" method="post">
<div id="box">
<p>Occasion:</p>
<?php
$rs=mysql_query('select DISTINCT occasion from cakes');
?>
<select name="occasion"onchange='location=this.options[this.selectedIndex].value;'>
<?php
$path="filter1.php?search=";
while($record=mysql_fetch_assoc($rs)){
?>
<option value="<?php echo $path.$record['occasion']; ?>"><?php echo $record['occasion']; ?></option>
<?php
}
?>
</select>
</div>
<div id="box">
<p>Styles:</p>
<?php
$rs=mysql_query('select DISTINCT style from cakes');
?>
<select name="style" onchange='location=this.options[this.selectedIndex].value;'>
<?php
$path="filter1.php?choice=";
while($record=mysql_fetch_assoc($rs)){
?>
<p><option value="<?php echo $path.$record['style']; ?>"><?php echo $record['style']; ?></option></p>
<?php
}
?>
</select>
</div>
<div id="box">
<p>Colours:</p>
<?php
$rs=mysql_query('select DISTINCT colour from cakes');
?>
<select name="colour" onchange='location=this.options[this.selectedIndex].value;'>
<?php
$path="filter1.php?choice=";
while($record=mysql_fetch_assoc($rs)){
?>
<p><option value="<?php echo $path.$record['colour']; ?>"><?php echo $record['colour']; ?></option></p>
<?php
}
?>
</select>
</div>
<div id="box">
<p>Filling:</p>
<?php
$rs=mysql_query('select DISTINCT filling from cakes');
?>
<select name="filling"
onchange='location=this.options[this.selectedIndex].value;' >
<?php
$path="filter1.php?choice=";
while($record=mysql_fetch_assoc($rs)){
?>
<p><option value="<?php echo $path.$record['filling']; ?>"><?php echo $record['filling']; ?></option></p>
<?php
}
?>
</select>
<p>
</div>
<div id="box">
<p>Topping:</p>
<?php
$rs=mysql_query('select DISTINCT topping from cakes');
?>
<select name="topping"
onchange='location=this.options[this.selectedIndex].value;' >
<?php
$path="filter1.php?choice=";
while($record=mysql_fetch_assoc($rs)){
?>
<p><option value="<?php echo $path.$record['topping']; ?>"><?php echo $record['topping']; ?></option></p>
<?php
}
?>
</select>
<p>
</div>
</form>