Magento - 强制表单字段将大写值发送到数据库

我们想强制注册表单字段输入全部为大写，我<?php @$_REQUEST['firstname'] = strtoupper(@$_REQUEST['firstname']); ?>尝试了这段代码，但它没有帮助。我错过了我们的东西吗？

<div class="field name-firstname">
<?php @$_REQUEST['firstname'] = strtoupper(@$_REQUEST['firstname']); ?>    
    <label for="<?php echo $this->getFieldId('firstname')?>" class="required"><em>*</em><?php echo $this->getStoreLabel('firstname') ?></label>
    <div class="input-box">
        <input type="text" id="<?php echo $this->getFieldId('firstname')?>" name="<?php echo $this->getFieldName('firstname')?>" value="<?php echo $this->escapeHtml($this->getObject()->getFirstname()) ?>" title="<?php echo $this->getStoreLabel('firstname') ?>" maxlength="255" class="input-text <?php echo $this->helper('customer/address')->getAttributeValidationClass('firstname') ?>" <?php echo $this->getFieldParams() ?> />
    </div>
</div>