Recently upgraded from Magento CE 1.5 to Magento 1.9.0.1. I kept the original 1.5 custom theme which was done by someone else. Starting receiving emails a few days later from customers on IE11 who were complaining of the checkout "freezing up" or not allowing them to continue. Here is a screenshot of what the customer sees.
I fired up IE11 and opened the inspector which revealed the following errors;
After comparing the console errors to Chrome and Firefox, I determined that the errors present in IE11 but not in others. The error is:
Unable to get property 'reject' of undefined or null reference.
After some Googling, this seems to be a very ambiguous error. Has anyone experienced a similar problem after upgrading? Thank you.
Best Answer
deprecation.js is not part of magento and prototype might not be IE11 compatible https://prototype.lighthouseapp.com/projects/8886/tickets/3508-ie11-support