jquery unhide on the value of a select drop down

jquery unhide on the value of a select drop down

I want to get at the value of a select box on change and hide or unhide another elemen in the same form determined on value selected so far I have something that doesn't even trigger.....
if the content of "arrival" is VIP I want to unhide "arrival_time" 
eg the form contains
<p><label for="id_arrival">Arrival:</label> <select name="arrival" id="id_arrival"><option value="" selected="selected">---------</option> <option value="1">STD</option> <option value="2">VIP</option> </select></p>
<p><label for="arrival_time">Arrival time:</label> <select name="arrival_time" id="id_arrival_time"> <option value="" selected="selected">---------</option> <option value="1">08:00</option> <option value="2">09:00</option> </select></p>
so far this does not trigger at all

    <script>
        function(getVals){
            var sv = $('#id_arrival').val();
            alert("YYYYYYY")
            if sv = "VIP"{
                alert('XXXXXXXXX');
            }
        }
        $("select").change( getVals );
</script>
Haing many selects in the form probably doesn't help and I want to try to keep {{ form.as_p }} is the template if at all possible

tried this as well
        $('#id_arrival').('change', function() {
            alert( this.value };
        });
no trigger

Appreciate any help