The library that it's loaded by your CKEditor plugin (http://latex.codecogs.com/js/eq_editor-lite-16.js) defines a global "URL" object that it's overwritting the native window.URL object available in new browsers
https://developer.mozilla.org/en-US/docs/Web/API/Window.URL
It would be great if you could fix your code to rename that object to something that doesn't causes problems :-D
Thanks