I am in the process of testing a Magento 1.3 site using Magento 1.4. I am seeing very weird and inconsistent behavior. Instead of including the URL of my javascript files, M
I had the same Problem.
Its because magento can't find a javascript file. Look at your /var/log/exception.log (You have to enable the log in System -> Config -> Developer Options)
In my log was the following error:
exception 'Exception' with message 'Warning: filemtime() [function.filemtime]: stat failed for /var/www/js/calendar/lang/calendar-en.js in /var/www/app/code/core/Mage/Core/Helper/Data.php on line 631' in /var/www/app/code/core/Mage/Core/functions.php:245
So I created the file and voila it works !