Firefox 18 Boasts a Superfast IonMonkey JavaScript JIT and Preliminary WebRTC Support

The latest version of the browser has landed in the stable channel

With the holidays over and 2013 on its way, Mozilla is back at work and the results are already visible, the latest stable version of Firefox is almost here. Firefox 18 is ready and available for download if you know where to look, Mozilla hasn't made the official announcement.

It makes little difference, the new features and improvements in Firefox 18 have been long in the works.

The big new feature in the latest Firefox is the IonMonkey JavaScript JIT compiler that should provide a speed boost to all JavaScript-heavy sites, which are most websites these days.

Mac users should be happy with the new support for Retina displays, which should make Firefox look great on high definition displays and also improve how web pages are rendered on devices sporting these screens.

Firefox 18 also boasts preliminary support for WebRTC, just like Mozilla boasted a few months back along with smaller improvements like a new image scaling algorithm, based on Chrome's. On the security front, Firefox 18 blocks mixed scripting content by default.


IonMonkey has been in the works for a while now, but the wait was worth it. Mozilla completely re-engineered its just-in-time JavaScript compiler to not only make it faster but also more flexible.

The immediate result is a speed boost, a significant one. But perhaps even more important is the ability to improve, add or change the optimization algorithms used by the JIT without completely rewriting it.

This modular approach should make it a lot easier to gain performance in the future. You can read more about IonMonkey here.


The other big feature in Firefox 18 is WebRTC, a new web technology which will enable web apps to initiate communication channels across browsers, i.e. make possible fully web-based Skype which doesn't require any plugin.

Mozilla boasted that it would have full support for the nascent technology by the end of 2012. It's 2013 already, obviously, but it's safe to say Mozilla achieved its goal.

Though, even that is relative, Firefox offers support for getUserMedia (prefixed) – which handles the webcam and the mic, peerConnection (also prefixed) – which handles the audio and video data streams between the people in the conversation, and Data Channel – which enables the participants to send any data they want, peer to peer.

Firefox is now the most far along browser in supporting WebRTC, but the proposed specs are still evolving and it's still very experimental which is why Mozilla calls it "preliminary" support. That said, almost everything that can currently work in WebRTC does so in Firefox.

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