Site Compatibility for Firefox 23 | MDN

Firefox 23 Aurora (pre-Beta) will be released on May 17, 2013. While it has been developed to maintain compatibility as much as possible, the new version includes some changes affecting backward compatibility aimed at improving interoperability with the other browsers or following the latest Web standards. Here's the list of such changes — Hope this helps whenever you test your sites or applications.

This article only explains the changes that may affect backward compatibility for Websites. For the other new features and changes, please read the following documents:

This list may be updated until the release of the final version on August 6, 2013, so please check back later.

Security & Privacy Non-SSL contents on SSL pages are blocked by default Firefox 18 introduced preferences to block loading contents from non-SSL (http) sites on SSL (https) pages. One of those preferences, security.mixed_content.block_active_content is now enabled by default in order to enhance user security. That means insecure scripts, stylesheets, plug-in contents, inline frames, Web fonts and WebSockets are blocked on secure pages, and a notification is displayed instead. JavaScript Locale sensitive methods have been reimplemented The String.localeCompare, Number.toLocaleString, Date.toLocaleString, Date.toLocaleDateString, and Date.toLocaleTimeString methods have been reimplemented as a part of the full implementation of the ECMAScript Internationalization API. These methods now accept locales and options arguments, which let applications tailor their behavior. Applications that have provided arguments in the positions used for locales and options, which in the past were ignored, may now see that these arguments have effects, including exceptions for invalid input.