[jQuery] How to add unique options to select?

[jQuery] How to add unique options to select?


Hi,
I have a form with a select element that contains province names.
If I click a text, an Ajax call rertieves an XML string with all
present provinces in the database.I loop over the nodes in the XML and
append them to the <select> element. That works. Only, when I click a
second time, all the provinces get appended to the select so I end up
with duplicate items.
So I want to check: if the <select> does _not_ contain an <option>
element with the value I currently look at (in the XML node) add it,
else don't.
This is my code:
    $("#updateProvinces").click(function(){
                $.get(
                    "http://lab.local/login.cfc",
                    {method:"getProvinces"},
                    function(xml){
                        var select = $("form[name='cityform'] select[name='province']");
                        $(xml).find('province').each(function(){
                            if($(select +"/option[@id!="+$(this).attr('id')+"]")){
                                select.append("<option value="+$(this).attr('id')+">"+$
(this).attr('name')+"</option>");
                            }
                        })
                    }
                )
            })
Below is the part of the form with the select and update element:
<form name="cityform" method="post">
    <table>
        <tr>
            <td>Provincie:</td>
            <td>
                <select name="province">
                </select>&nbsp;<p id="updateProvinces">update
            </td>
        </tr>
This does not work, it gets appended anyway. I guess
if($(select +"/option[@id!="+$(this).attr('id')+"]")){
is not correct. Does anyone know how conditionally append an item to
te select element?
Thanks