Onchange Jquery event condition for dropdown - php

Question

I am working on a dropdown change event, but I am not able to set a condition for the change event. For the second dropdown(subsel) I want a list of values for which the value in sel is NOT present. So far all I'm able to do is reflect the value in first select dropdown into the second dropdown.
<script>$(document).ready(function() {
$("#sel").live('change', function() {
$("#selsub").val($(this).val());
});
});</script>
<form method="get">
<label for="category">Parent Category</label>
<select name="sel" id="sel">
<?php
include('connection.php');
$query_parent=$query=mysql_query("SELECT * from stations");
<?php while($row = mysql_fetch_array($query_parent)): ?>
<option value="<?php echo $row['name']; ?>"><?php echo $row['name']; ?></option>
<?php endwhile;?>
</select>
<br/><br/>
<label>Sub Category</label>
<div class='detail'>
<select name="selsub" id="selsub">
<?php
$query=mysql_query("SELECT * from stations");
while($row1 = mysql_fetch_array($query)): ?>
<option value="<?php echo $row1['name']; ?>"><?php echo $row1['name']; ?></option>
<?php endwhile; ?>
</select>
</div>
Kindly help me to set a condition where in the second dropdown(selsub) all the values would appear except the value one in first dropdown(sel).

Answer 1

Try to do:
$(document).ready(function() {
$("#sel").on('change', function() {
selectedVal = this.value;
$("#selsub option[value='" + selectedVal +"']").hide();
});
});