基于产品页面的类别ID magento的条件加载内容

我想有条件地根据产品页面中的类别ID加载内容，但是无法正常工作.我知道我可以通过调用自定义属性来做到这一点，但这并不是我要记住的，因为内容专门针对特定类别，因此我不想在给定类别的每种产品中重复输入.

I want to conditionally load content based on category id in product page but can't get it to work. I know I can do this by calling a custom attribute but this is not what I have in mind because the content is specifically for a particular category so I don't want to enter it repeatedly in each product for the given category.

基本上我正在寻找这样的东西:

Basically I was looking for something like this:

<?php if ($_catid = $this->getCategoryid('3')):?>
display content for category id 3 (content is entered directly in the view.phtml file)
<?php else: ?>
content for other cateogegory
<?php endif; ?>

非常感谢您的指导！

更新正确的代码(感谢ahadley):

Update for the correct code (thanks ahadley):

<?php $category = Mage::getModel('catalog/layer')->getCurrentCategory();?>
<?php if($category->getId()==3): ?>

<h3>Show content for Category ID3</h3>

<?php else: ?>

<h3>Show content for other categories</h3>
<p>consectetuer adipiscing elit. </p>

<?php endif; ?>