echo '<pre>';
print_r($array);
echo '</pre>';

But did you know that in Zend Framework there’s a built in Zend_Debug?

Zend_Debug::dump($array);

Does pretty much the same thing!

Another bad way to debug is to dump only ids from some database table or loop index. At least write something before that, something like:

alert('on the: ' + index + ' happened something!');

that gives you more and can improve your work so much.