JQuery refresh select box

You may use

$('#select').removeAttr('selected').find('option:first').attr('selected', 'selected');

Hi after several research, I solved with this piece of code:

$('#select_id').empty();    
$('#select_id').append($('<option>',{text: 'pippo', value: 'pippo', selected: true}))
$('#select_id').change();

Hope it helps.

You can add a "selected" attribute to the option element you'd like to be selected:

$('#select')
    .append('<option value="' + result + '" selected="selected">' + result + '</option>'); 

You don't specify how you populate exactly you select element, using a loop, you could do like this:

var data = ['a', 'b', 'c'];
var $select = $('#select'); // you might wanna empty it first with .empty()

for (var i = 0; i < data.length; i++) {
    var o = $('<option/>', { value: data[i] })
        .text(data[i])
        .prop('selected', i == 0);
    o.appendTo($select);
}​

DEMO

---

So it seems you are using jQuery Mobile like you said in the comment.

If you are using the selectmenu widget, you need to programmatically refresh after you make programmatic change to its content/structure:

$select.selectmenu("refresh", true);

Documentation

Simply .. you set the value whatever you want , i.e : $('#select').val(5); .. so in your case its $('#select').val(result);

Edit : a full working example included :

<script type='text/javascript' src='http://code.jquery.com/jquery-1.6.4.js'></script>
<select id='select'></select>
<br>
<input type=button onclick='addNew()' value='Add'>

<script>
function addNew()
{
        var result = Math.floor(Math.random()*1000);
        $('#select').append('<option value="' + result + '">' + result + '</option>'); 
        $('#select').val(result);           
} 
</script>

​