@deplantage This needs to be done on the browser level
http://net-informations.com/js/basics/enable.htm
Alternatively, this may be caused by combining/compressing javascript. In case you use such an extension, please disable it and clear your server cache. It also can be caused by some 3rd Party extensions. The only advice I can give you is to disable third party extensions one by one, clearing server cache each time, until you find the culprit.