Select2 Demo

by koh_edwin

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/select2/3.5.2/select2.min.js"></script>
<link rel="stylesheet" href="http://cdnjs.cloudflare.com/ajax/libs/select2/3.5.2/select2.min.css">
<input type="hidden" id="fruitSelect" value="" style="width:300px;" /><br />
<br />
<button type="button" id="showValue">Show Value</button><br />
<br />
<div id="output">
</div>

JavaScript

var FRUIT_GROUPS = [
    {
        id: '',
        text: 'Citrus',
        children: [
            { id: 'c1', text: 'Grapefruit' },
            { id: 'c2', text: 'Orange' },
            { id: 'c3', text: 'Lemon' },
            { id: 'c4', text: 'Lime' }
        ]
    },
    {
        id: '',
        text: 'Other',
        children: [
            { id: 'o1', text: 'Apple' },
            { id: 'o2', text: 'Mango' },
            { id: 'o3', text: 'Banana' }
        ]
    }
];

$('#fruitSelect').select2({
    multiple: true,
    placeholder: "Select fruits...",
    data: FRUIT_GROUPS,
    query: function(options) {
        var selectedIds = options.element.select2('val');
        var selectableGroups = $.map(this.data, function(group) {
            var areChildrenAllSelected = false;
            $.each(group.children, function(i, child) {
                if (selectedIds.indexOf(child.id) < 0) {
                    areChildrenAllSelected = false;
                    return false; // Short-circuit $.each()
                }
           });
            return !areChildrenAllSelected ? group : null;
        });
        options.callback({ results: selectableGroups });
    }
}).on('select2-selecting', function(e) {
    var $select = $(this);
    if (e.val == '') {
        e.preventDefault();
        $select.select2('data', $select.select2('data').concat(e.choice.children));
        $select.select2('close');
    }
});

$('#showValue').click(function() {
    $('#output').text($('#fruitSelect').val());
});