Selecting values from a multiselect not working in webkit

Question

Hello!

The code below works fine in Firefox. However in Chrome and Safari it doesn't.

Essentially it returns an array of values, then selects them from multiselect. However in Chrome and safari it doesn't select the items from the multiselect.

    $('form#movie select#movie_movie').click(function(){
    var id = $(this).val();
    $("#movie_category option:selected").attr('selected', '');
    $("#movie_model option:selected").attr('selected', '');
    $("#movie_gallery option:selected").attr('selected', '');
    $("#movie_playlist option:selected").attr('selected', '');

    if (id != 0) {
        $.ajax({
            type: 'POST',
            url: "/administration/link/movie/id/"+id,
            dataType: 'json',
             beforeSend: function(x) {
                $.blockUI({theme: true, title: 'Loading', message: '<p>Please wait...</p>', timeout: 1000});
                if(x && x.overrideMimeType) {
                    x.overrideMimeType("application/json;charset=UTF-8");
                }
             },
            error: function() {
                $.unblockUI();
                alert('Error loading object, please try again');
            },
            success: function(returned_values) {
                 $.unblockUI();
                 $.each(returned_values.object.playlist || {}, function(i, item) {$("#movie_playlist option[value='"+item+"']").attr('selected', 'selected');});
                 $.each(returned_values.object.category || {}, function(i, item) {$("#movie_category option[value='"+item+"']").attr('selected', 'selected');});
                 $.each(returned_values.object.model || {}, function(i, item) {$("#movie_model option[value='"+item+"']").attr('selected', 'selected');});
                 $.each(returned_values.object.gallery || {}, function(i, item) {$("#movie_gallery option[value='"+item+"']").attr('selected', 'selected');});

            }
        });
    }
});

So the part that isn't working in them is:

$("#movie_playlist option[value='"+item+"']").attr('selected', 'selected');

Any ideas??