Magento Date of Birth drop down boxes

dob.phtml

<?php
/**
 * @author    iamncla @ github.com
 * @see Mage_Customer_Block_Widget_Dob
 */
?>
<label for="<?php echo $this->getFieldId('month')?>"<?php if ($this->isRequired()) { echo ' class="required"'; } ?>><?php echo $this->__('Birthday') ?></label>
<div class="customer-dob">
  <div class="dob-month">
    <select name="<?php echo $this->getFieldName('month'); ?>" id="<?php echo $this->getFieldId('month'); ?>">
      <option value="">MM</option>
      <?php for ($i = 1; $i <= 12; $i++): ?>
      <?php $month = (strlen($i) == 1) ? "0".$i : $i; ?>
        <option value="<?php echo $month; ?>" <?php echo ($i==$this->getMonth()) ? "selected" : ""; ?>><?php echo $month; ?></option>
      <?php endfor; ?>
    </select>
  </div>
  <div class="dob-day">
    <select name="<?php echo $this->getFieldName('day'); ?>" id="<?php echo $this->getFieldId('day'); ?>">
      <option value="">DD</option>
      <?php for ($i = 1; $i <= 31; $i++): ?>
      <?php $day = (strlen($i) == 1) ? "0" . $i : $i; ?>
        <option value="<?php echo $day; ?>" <?php echo ($i==$this->getDay()) ? "selected" : ""; ?>><?php echo $day; ?></option>
      <?php endfor; ?>
    </select>
  </div>
  <div class="dob-year">
    <?php $currentYear = intval(date("Y")); ?>
    <select name="<?php echo $this->getFieldName('year'); ?>" id="<?php echo $this->getFieldId('year'); ?>">
      <option value="">YYYY</option>
      <?php for ($i = $currentYear; $i >= $currentYear - 60; $i--): ?>
        <option value="<?php echo $i; ?>" <?php echo ($i==$this->getYear()) ? "selected" : ""; ?>><?php echo $i; ?></option>
      <?php endfor; ?>
    </select>
  </div>
  <div class="dob-full" style="display:none;">
    <input type="hidden" id="<?php echo $this->getFieldId('dob')?>" name="<?php echo $this->getFieldName('dob')?>" />
  </div>
  <div class="validation-advice" style="display:none;"></div>
</div>
<script type="text/javascript">
//<![CDATA[
    var DOBSelects = Class.create(Varien.DOB, {
       initialize: function(selector, required, format) {
            var el = $$(selector)[0];
            var container       = {};
            container.day       = Element.select(el, '.dob-day select')[0];
            container.month     = Element.select(el, '.dob-month select')[0];
            container.year      = Element.select(el, '.dob-year select')[0];
            container.full      = Element.select(el, '.dob-full input')[0];
            container.advice    = Element.select(el, '.validation-advice')[0];
            new Varien.DateElement('container', container, required, format);
        }      
    });
    var customer_dob = new DOBSelects('.customer-dob', <?php echo $this->isRequired() ? 'true' : 'false' ?>, '<?php echo $this->getDateFormat() ?>');
//]]>
</script>