Sometimes you find your self in the need to determine if the current page a visitor is viewing is of a category or not. The reason for this could drastically very, but one good reason is the need for a global element not be shown on any category page.
It would be much faster to simply include this element or rather custom block globally to your Magento store via your layout XML files, and have a condition in this block’s .phtml file that excluded any output on category page.
This is a very simple method that simply looks to our Mage registry and asks the question “Is the current page indeed a current category page or not?”.
php if(!Mage::registry('current_category')):?>
//OUTPUT THE GLOBAL ELEMENTS CODE ON NONE-CATEGORY PAGES
php endif; ?>Simple as that, of course the correct way would be to include this block globally via your XML layout files, and then remove it via XML (Custom Layout Update) in the backend->catalog->manage categories “Custom Design” tab for each category.
But this method might be faster.
Devin R. Olsen