<div id="inner">
    <?php echo TbHtml::textFieldControlGroup("Choice[0]", '', array('label' => Yii::t('admin', 'Choice Number {number}', array("{number}" => 1)))); ?>
</div>
<?php echo CHtml::link('Add another option...', '#', array("onclick" => "addAnotherChoice(); return false;")); ?>

<script >
    var currentFieldCount = 1;
    function addAnotherChoice() {
        var field = '<div class="form-group"><label class="control-label" for="Choice[#NUMBER]">Choice Number #LABELNUMBER</label><div class="controls"><input class="form-control" type="text" value="" name="Choice[#NUMBER]" id="Choice_#NUMBER"></div></div>';

        field = field.replace(/\#NUMBER/g, currentFieldCount);
        field = field.replace(/\#LABELNUMBER/g, currentFieldCount + 1);
        $('#question_options #inner').append(field);
        currentFieldCount++;
    }
</script>