In Safari, Go to Insert>Media, try to enter something in the search box.
you will get the following error in the console and wont be able to place your cursor in to the search box:
api.php:1TypeError: 'undefined' is not a function (evaluating 'jQuery111102360369882080704_1410208128038({"warnings":{"main":{"*":"Unrecognized parameter: 'uselang'"}},"query":{"searchinfo":{"totalhits":0}}})')
Version: unspecified
Severity: major