var shows = Ext.create('Ext.data.Store', {
    fields: ['id','show'],
    data: [
        {id: 0, show: 'Battlestar Galactica'},
        {id: 1, show: 'Doctor Who'},
        {id: 2, show: 'Farscape'},
        {id: 3, show: 'Firefly'},
        {id: 4, show: 'Star Trek'},
        {id: 5, show: 'Star Wars: Christmas Special'}
    ]
});

Ext.create('Ext.form.Panel', {
    renderTo: Ext.getBody(),
    title: 'Sci-Fi Television',
    height: 200,
    width: 500,
    items: [{
        xtype: 'tagfield',
        fieldLabel: 'Select a Show',
        store: shows,
        displayField: 'show',
        valueField: 'id',
        queryMode: 'local',
        filterPickList: true
    }, {
        xtype: 'button',
        text: 'click me',
        handler: function(btn) {
            var tagfield = btn.up().items.getAt(0);
            var submitValue = tagfield.getSubmitValue();
            console.log('is array: ' + Ext.isArray(submitValue));
            console.log(submitValue);
        },
        scope: this
    }]
});