Sort Options in a Select List with javascript/jQuery.. but not alphabetically

Question

I am looking for a function that will take a list of options in a select list and sort them alphabetically but with a twist. All values with the text 'NA' should be pushed to the bottom of the list.

So given a list -

<select>
    <option value="1">Car</option>
    <option value="2">Bus</option>
    <option value="3">NA</option>
    <option value="4">Bike</option>
    <option value="5">Tractor</option>
    <option value="6">NA</option>
</select>

We should end up with -

<select>
    <option value="4">Bike</option>
    <option value="2">Bus</option>
    <option value="1">Car</option>
    <option value="5">Tractor</option>
    <option value="3">NA</option>
    <option value="6">NA</option>
</select>

The order of the NAs is not important.

And don't ask why I cannot just remove the NAs (or why there will be several options with the same texts but different underlying values, because I don't agree with it either.

Answer 1

demo: http://jsfiddle.net/4bvVz/

function NASort(a, b) {    
    if (a.innerHTML == 'NA') {
        return 1;   
    }
    else if (b.innerHTML == 'NA') {
        return -1;   
    }       
    return (a.innerHTML > b.innerHTML) ? 1 : -1;
};

$('select option').sort(NASort).appendTo('select');

Answer 2

var sb = $('select');

sb.append(sb.find('option').sort(function(a, b){
    return (
        a = $(a).text(),
        b = $(b).text(),
        a == 'NA' ? 1 : b == 'NA' ? -1 : 0|a > b
    );
}));